Whoa!!!!! what a miss by Lionel MESSI of al people!!

 

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SIWESS and PROJECT TOPICS WITH MATEERIALS

 for your SIWESS technical reports or project reports, contact us we are just a stone throw away. 07060484709

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fire!!!!

 

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Black holes

Do you know that stars also die? What happens when a star dies?  Yes! Stars can die; when a star dies they form a massive whole called the Black holes. When a star has exhausted the internal thermonuclear fuels in its core at the end of its life, the core becomes unstable and gravitationally collapses inward upon itself, and the star's outer layers are blown away leading to the creation of black hole.

The existence of black hole was first predicted by ALBERT Einstein in 1916, through his general theory of relativity. The term "black hole" was coined many years later in 1967 by American astronomer John Wheeler. After decades of black holes being known only as theoretical objects, the first physical black hole ever discovered was spotted in 1971. 

Then, in 2019 the Event Horizon Telescope (EHT) collaboration released the first image ever recorded of a black hole. The EHT saw the black hole in the center of galaxy M87 while the telescope was examining the event horizon, or the area past which nothing can escape from a black hole. The image maps the sudden loss of photons (particles of light). It also opens up a whole new area of research in black holes, now that astronomers know what a black hole looks like.

 

 

 

 

There are four types of black holes: stellar, intermediate, supermassive, and miniature. The most commonly known way a black hole forms is by stellar death. Black holes are some of the strangest and most fascinating objects in outer space. They're extremely dense; with such strong gravitational attraction that even light cannot escape their grasp if it comes near enough. 

Stellar black holes — small but deadly

 

When a star burns through the last of its fuel, the object may collapse, or fall into itself just like the roof of a building collapsing into itself. For smaller stars (those up to about three times the sun's mass), the new core will become a neutron star or a white dwarf. But when a larger star collapses, it continues to compress and creates a stellar black hole.

Black holes formed by the collapse of individual stars are relatively small, but incredibly dense. One of these objects packs more than three times the mass of the sun into the diameter of a city. This leads to a crazy amount of gravitational force pulling on objects around the object. Stellar black holes then consume the dust and gas from their surrounding galaxies, which keeps them growing in size.

According the Harvard-Smithsonian Center for Astrophysics," the Milky Way contains a few hundred million" stellar black holes.

 

 

Super massive black holes — the birth of giant

Imaging a hole whose size is over millions and billions the size of the sun! Super massive black holes are enormous black holes whose size is over millions or even billions of times as massive as the sun, but are about the same size in diameter. Such black holes are thought to lie at the center of pretty much every galaxy, including the Milky Way.

Scientists aren't certain how such large black holes spawn. Once these giants have formed, they gather mass from the dust and gas around them, material that is plentiful in the center of galaxies, allowing them to grow to even more enormous sizes.

Super massive black holes may be the result of hundreds or thousands of tiny black holes that merge together. Large gas clouds could also be responsible, collapsing together and rapidly accreting mass. A third option is the collapse of a stellar cluster, a group of stars all falling together. Fourth, super massive black holes could arise from large clusters of dark matter. This is a substance that we can observe through its gravitational effect on other objects; however, we don't know what dark matter is composed of because it does not emit light and cannot be directly observed.

 

 

Intermediate black holes  — stuck in the middle

Scientists once thought that black holes came in only small and large sizes, but recent research has revealed the possibility that midsize, or intermediate, black holes (IMBHs) could exist. Such bodies could form when stars in a cluster collide in a chain reaction. Several of these IMBHs forming in the same region could then eventually fall together in the center of a galaxy and create a super massive black hole.

In 2014, astronomers found what appeared to be an intermediate-mass black hole in the arm of a spiral galaxy.

"Astronomers have been looking very hard for these medium-sized black holes," study co-author Tim Roberts, of the University of Durham in the United Kingdom, said in a statement. "There have been hints that they exist, but IMBHs have been acting like a long-lost relative that isn't interested in being found."

Newer research, from 2018, suggested that these IMBHs may exist in the heart of dwarf galaxies (or very small galaxies). Observations of 10 such galaxies (five of which were previously unknown to science before this latest survey) revealed X-ray activity — common in black holes — suggesting the presence of black holes of from 36,000 to 316,000 solar masses. The information came from the Sloan Digital Sky Survey, which examines about 1 million galaxies and can detect the kind of light often observed coming from black holes that are picking up nearby debris.

 

What do black holes look like? 

Black holes are strange regions where gravity is strong enough to bend light, warp space and distort time. 

Black holes have three "layers": the outer and inner event horizon, and the singularity.

The event horizon of a black hole is the boundary around the mouth of the black hole, past which light cannot escape. Once a particle crosses the event horizon, it cannot leave. Gravity is constant across the event horizon.

The inner region of a black hole, where the object's mass lies, is known as its singularity, the single point in space-time where the mass of the black hole is concentrated.

Scientists can't see black holes the way they can see stars and other objects in space. Instead, astronomers must rely on detecting the radiation black holes emit as dust and gas are drawn into the dense creatures. But super massive black holes, lying in the center of a galaxy, may become shrouded by the thick dust and gas around them, which can block the telltale emissions.

Sometimes, as matter is drawn toward a black hole, it ricochets off the event horizon and is hurled outward, rather than being tugged into the maw. Bright jets of material traveling at near-relativistic speeds are created. Although the black hole remains unseen, these powerful jets can be viewed from great distances.

The Event Horizon Telescope's image of a black hole in M87 (released in 2019) was an extraordinary effort, requiring two years of research even after the images were taken. That's because the collaboration of telescopes, which stretches across many observatories worldwide, produces an astounding amount of data that is too large to transfer by internet. 

With time, researchers expect to image other black holes and build up a repository of what the objects look like. The next target is likely Sagittarius A*, which is the black hole in the center of our own Milky Way galaxy. Sagittarius A* is intriguing because it is quieter than expected, which may be due to magnetic fields smothering its activity, a 2019 study reported. Another study that year showed that a cool gas halo surrounds Sagittarius A*, which gives unprecedented insight into what the environment around a black hole looks like.

 

Weird facts about black holes

·         If you fell into a black hole, theory has long suggested that gravity would stretch you out like spaghetti, though your death would come before you reached the singularity. But a 2012 study published in the journal Nature suggested that quantum effects would cause the event horizon to act much like a wall of fire, which would instantly burn you to death.

·         Black holes don't suck. Suction is caused by pulling something into a vacuum, which the massive black hole definitely is not. Instead, objects fall into them just as they fall toward anything that exerts gravity, like the Earth.

·         The first object considered to be a black hole is Cygnus X-1. Cygnus X-1 was the subject of a 1974 friendly wager between Stephen Hawking and fellow physicist Kip Thorne, with Hawking betting that the source was not a black hole. In 1990, Hawking conceded defeat.

·         Miniature black holes may have formed immediately after the Big Bang. Rapidly expanding space may have squeezed some regions into tiny, dense black holes less massive than the sun.

·         If a star passes too close to a black hole, the star can be torn apart.

·         Astronomers estimate that the Milky Way has anywhere from 10 million to 1 billion stellar black holes, with masses roughly three times that of the sun.

·         Black holes remain terrific fodder for science fiction books and movies. Check out the movie "Interstellar," which relied heavily on Thorne to incorporate science. Thorne's work with the movie's special effects team led to scientists' improved understanding of how distant stars might appear when seen near a fast-spinning black hole.

 

 

10 FUN FACTS ABOUT BLACK HOLES!

1. You Can’t Directly See a Black Hole.

A black hole is called a black hole because of it’s color, especially since light can’t escape. What we can see, though, is the effects of a black hole. Analyzing the surrounding area of a black hole, we can see its effects upon its environment. For example, a star that’s close enough to a black hole can be seen being ripped apart.

2. Our Milky Way Probably Has a Black Hole.

But, don’t be alarmed, Earth isn’t in danger! The major black hole that astronomists believe to be within our Milky Way is light years away from Earth.

3. Dying Stars Lead to Stellar Black Holes.

The death of large stars lead to black holes, because a star’s gravity will overwhelm the star’s natural pressure that it maintains to keep its shape. When the pressure from the nuclear reactions collapses, gravity overwhelms and collapses the star’s core, and the star’s other layers are thrown off into space, and this process is also known as a supernova. The remainder of the core collapses, a spot overcome by density and without volume – a black hole.

·         4. There are Three Categories of Black Holes.

·          Primordial Black holes – These are the smallest of black holes and range from an atom’s size to a mountain’s mass.

·          Stellar Black Holes – These are the most common of black holes and they can be up to 20 times more massive than the Sun. There are also a variety of these all over the Milky Way.

·          Supermassive Black Holes – These are the largest of black holes, being more than 1 million times more massive than the Sun.

·          Black Holes Are Funky.

·         Say someone falls into a black hole and there’s an observer that witnesses this. The person who fell into the black hole’s time slows down, relative to the person watching. This is explained by Einstein’s Theory of General Relativity, which states that time is affected by how fast you are going when you’re at extreme speeds close to light.

·          The First Black Hole Wasn’t Discovered Until X-Ray Astronomy was Used.

·         Cygnus X-1 was the first black hole discovered in the 1960’s, and it’s 10 times more massive than the Sun.

·          The Closest Black Hole is Probably Not 1,600 Light-Years Away.

·         V4647 Sagitarii was thought to be 1,600 light-years away, but is further away than expected. Scientists now believe that this black hole is about 20,000 light years away.

·         We Don’t Know if Wormholes Exist.

·         We don’t know if this event exists, since we don’t know too much about physics, but that also means that anything may be possible.

·          Black Holes Are Only Dangerous if You Get Too Close.

·         Black holes are safe to observe from a lengthy distance, but not if you get too close, which also means that it’s unlikely for a black hole to consume an entire universe.

·          Black Holes Are Constantly Used in Science Fiction.

 

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FECAL DUST

 

Fecal dust

Do you know that the air we breathe in can sometimes contain tiny particles of feaces?

When the buttocks is wiped with tissue after defecation, little quantity of the feaces would be left on the tissue or paper, on drying it acquires a light weight so that it easily be carried about by the winds. Another situation is that this dust through friction will adhere to surfaces as it moves about contaminating thereby causing different disease like UTI,

It comes from fecal residue, left after incomplete wiping. Through drying and friction it turns out to dust, going to all surfaces, at first stage the urogenital organs, causing UTI, and later to all house, causing food contamination. Other times it can be spread through the activity of dust mites in the soil.

Dust mites

 

That phenomenon is more intense in hospitals, because the patients are usually debilitated, weak, with mobility restriction etc, particularly if there are hemorrhoids or anus hair and are unable to wipe properly (if there is such a thing).So the dust flying reaches to all ward surfaces, dispersing its pathogenic microbes and being the cause of the known HAI. It is obvious that the known hygiene measures, as is hand washing etc is not enough.

Up to now not a scientific study have ever doubted FECAL DUST's existence and its role on microbe dispersion, however no hygiene measures are imposed or any relative medical explanation or advice is given, particularly to women, or any guiding to hospital hygiene managers.

 

Fecal dusts being carried by wind

 

In West Africa districts and the surrounding area, has long been afflicted by pollutions from fecal dust caused by open defecations that environmental health officers or regulators have chosen to ignore or cannot control properly due to shortage of manpower. While it may seem a quaint issue, fecal dust from concentrated animal feeding operations has a huge impact on the respiratory health of those living in the region. Imagine villages where there is no proper toilet facilities, these people practice open defecation which in turn have a way of affecting their health without then knowing. Again because their economy is centered around the cattle rearing, with seemingly endless cattle pastures, they stand a higher risk of being infected by the microorganisms being transported in fecal dust. When these villagers go on open defecation, the aridity of the region has dried the fecal matter from their feaces and sent it airborne, into neighboring communities and residents’ lungs. This cloud settles over towns in the afternoon, permeating the air with a strong odor and thick haze that strains breathing.

The true danger of this haze is often less visible: the inhalation of ammonia and small particulates, which has been proven to have serious health outcomes. Some of the possible health impacts are asthma, heart conditions, difficulty breathing, and premature death in citizens with heart or lung disease. In Nigeria, there has been a serious lack of data and study on the link between fecal dust and asthma, because fecal dust levels are not being monitored. Epidemiological studies have been conducted in different part of the country have shown that the levels of asthma, heart conditions, and premature deaths are disproportionately large, and that airborne disease is the predominant cause of asthma in many state. One study found that doubling livestock production in an area caused a 7.4% increase in infant mortality due to respiratory disease. Another found that children living in the villages were at a far higher risk of developing asthma.

 

Microorganisms commonly found in fecal dust leading respiratory tract infections

 

While ammonia and small particulates are generally regulated; animal dung commonly used by farmers as manure is not seen as a pollutant to these farmers. This allows cattle breeders to pollute freely and indiscriminately, without facing the consequences other industries are subject to. Even worse, the level of fecal dust is the air is not monitored so doctors and health experts have no way of knowing the amount of ammonia and other dangerous particulates that people are inhaling. Despite repeated complaints from residents and the government, the Environmental health officers of State Health still does not monitor or test the impact of living near these contaminated areas or collect data on fecal dust output. The agency’s monitors are conspicuously absent from the area’s most affected by fecal dust, and studies have had to rely on independently collected data.

 

I propose that ammonia and particulates originating from animal and human excretal should be classified as a pollutant, and ammonia should be regulated as a criteria pollutant under the Clean Air Act, this will allow Environmental health officers to enforce the laws/ regulations banning open defecations, monitoring stations should be set up in each district and surrounding regions to collect data on levels of ammonia from fecal dust. This data should be made freely available for researchers and doctors and should also be used to enforce regulations on open defecators and cattle breeders. Given the density of the urban towns and cities, cattle grazing and the region’s dry environment, so any solution would be unprecedented. I propose that a cap-and-trade program on waste production would be the best option to limit the fecal dust in the air, with the initial permits being allocated according to historic pollution levels through a grandfathering system. Cap-and-Trade programs can approximate the most economically efficient solution while avoiding the label of “tax”. Cattle ranchers are able to abate airborne fecal dust through manure watering, conversion to fertilizer, and more frequent raking of the fields. The cap-and-trade program would incentivize ranchers to abate more of their pollution, as long as the abatement cost is lower than the market rate of a permit.

The major obstacle of this solution is measuring how much fecal dust each farm is outputting, as ranches are often adjacent and fecal dust is airborne. We should calculate their waste level by multiplying the number of cows by a coefficient that is determined by the conditions of their ranch and the abatement efforts they undertake. One major problem that would be encountered is the fact that Nigeria does not have or practice ranching. Cap-and-Trade is not perfectly suited for this issue, but a command-and-control regulation or tax on cattle is not politically possible in Nigeria. No solution to this issue is easy, but it is necessary to find one as the land is only becoming drier and the clouds of dust heavier as droughts increase due to climate change. Cap-and-Trade is the most feasible and efficient solution to provide the relief. By controlling the amounts of ammonia and small particulates in the air, we can help protect the health of rural citizens across the country.

 

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HORMONES

 

INTRODUCTION

HORMONE

These are organic substance secreted by plants and animals that functions in the regulation of physiological activities and in maintaining homeostasis. Hormones carry out their functions by evoking responses from specific organs or tissues that are adapted to react to minute quantities of them. The classical view of hormones is that they are transmitted to their targets in the bloodstream after discharge from the glands that secrete them. This mode of discharge (directly into the bloodstream) is called endocrine secretion. The meaning of the term hormone has been extended beyond the original definition of a blood-borne secretion, however, to include similar regulatory substances that are distributed by diffusion across cell membranes instead of by a blood system

AUXINS

These are a powerful growth hormone produced naturally by plants. They are found in shoot and root tips and promote cell division, stem and root growth. They can also drastically affect plant orientation by promoting cell division to one side of the plant in response to sunlight and gravity.

Auxins Have Four Key Effects on Plant Growth:

ü  Stimulating shoot elongation – Auxins positively influence gibberlins that promote cell elongation. This increases plant length. Essentially, gibberlins and thereby auxins, increase the distance between nodes, spacing the branch points further apart.
Controlling seedling orientation – It was the infamous Charles Darwin and his son Francis who first noticed that seedlings bend toward the light. However, whether a new shoot grows into the soil or towards light, depends on where auxins are located and how they influence cells within the plant. Auxins will move downward due to gravity and laterally, away from light. Cells grow more in areas of the plant where auxins are highly concentrated.

ü  Stimulating root branching – When an auxin is applied to a cut stem, the stem will initiate roots at the cut.

ü  Promoting fruit development – Auxins in the flower promote maturation of the ovary wall and promote steps in the full development of the fruit.

Fast growth of shoot: auxins is known to cause the shoot of plants to grow fast

ü  It causes epical dominace   

ü  Retention of fruits

ü  It induces flowering

ü  It induce root formation

ü  It breaks dominance in seeds

ü  It induce pathenocarpy

ü  Delay of abscission of seed formed and seed ripening

Auxins can be produced naturally (by the plant) or synthetically (in a lab). When produced synthetically, they can be used in high concentrations as a pesticide, causing drastic growth. The herbicide, 2-4-D, is an example of an auxin-based pesticide, specifically engineered to cause dicots (plants like dandelions) to grow quickly and uncontrollably, ultimately killing the plant.

GIBBERELLINS DEFINITION

“Gibberellins are any group of plant hormones that stimulate elongation of the stem, flowering and germination.”

Gibberellins (GAs) are plant hormones that regulate various developmental processes, including stem elongation, germination, dormancy, flowering, flower development, and leaf and fruit senescence. GAs are one of the longest-known classes of plant hormone

As, we humans have different types of hormones, a chemical messenger produced by the endocrine glands to perform several metabolic activities within the body.

Like humans, plants also have five major types of plant hormones which are collectively called as plant growth regulators, promoters, inhibitors, and phytohormones.

Gibberellins are the plant growth regulators involved in regulating the growth and influencing different developmental processes which include stem elongation, germination, flowering, enzyme induction, etc.

Gibberellins have different effects on plant growth and the stem elongation is the most dramatic amongst all.  The stem starts to grow when it is applied in low concentration to a bush. The internodes grow so long that the plants become indistinguishable from climbing. The Gibberellins overcome the genetic limitations in different dwarf varieties.

There are more than 70 gibberellins isolated. They are GA1, GA2, GA3 and so on. GA3 Gibberellic acid is the most widely studied plant growth regulators.

Gibberellin is a diterpenoid. It forms the basis of molecules such as vitamins A and E. The figure above shows the structure of the Gibberellin A1, the first identified gibberellin.

The structure of all the gibberellins is the same with several side groups attached. These groups determine the unique functions of gibberellins in different tissues.

FUNCTION OF GIBBERELLINS

Gibberellin function in plants

The important gibberellins function are mentioned below:

ü  Seed Germination

Some seeds that are sensitive to light such as tobacco and lettuce exhibit poor germination in the absence of sunlight. Germination begins rapidly if the seeds are exposed to the sunlight. If the seeds are treated with gibberellic acid, the light requirement can be overcome.

ü  Dormancy of Buds

The buds that are formed in autumn stay dormant until next spring. This dormancy can be overcome by treating them with gibberellin.

ü  Root Growth

Gibberellins have almost no effect on the growth of roots. However, some inhibition of growth can occur at a higher concentration in a few plants.

ü  Elongation of the Internodes

Internodes elongation is the most pronounced effects of gibberellins on plant growth. In many plants such as dwarf pea and maize, the genetic dwarfism can be overcome.

For example, the dwarf pea plants have expanded leaves and short internodes. But the internodes expand and look like tall plants when treated with gibberellin.

Gibberellins exhibit their impact by altering gene transcription.

The steps of gibberellin functions are mentioned below:

The GA enters the cell and binds to a soluble protein receptor.

This binds to a protein complex (SCF) that attaches ubiquitin to one or the other DELLA proteins.

This activates the destruction of DELLA proteins through proteasomes.

The destruction of DELLA proteins releases the inhibition and gene transcription starts.

This procedure is amongst different cases in biology where the pathway is turned on by inhibiting the pathway. However, most of the proteins that are involved differ according to circumstances, both auxin and gibberellins influence gene expression by a common mechanism of repression relief.

IT also promote the development of flowers

USES OF GIBBERELLINS

Gibberellin is commercially obtained from fungi. It is used to facilitate the germination of seeds.

It is sprayed on the grapevines and used to enlarge them.

It is used on cucumber plants to produce all-male flowers. This helps the farmers to obtain pollen of desired characteristics to be used for hybridization.

Biennial plants produce flowers only during low temperatures. When gibberellin is applied, these plants will flower irrespective of the low temperatures.

The dwarf varieties of plants which are genetic mutants can be made to grow by applying gibberellins to them.

KINETIN

Is a cytokinin. Cytokinins are compounds that stimulate plants to grow. Kinetin occurs naturally in humans and is sometimes used to make medicine.
People use kinetin most often for aging skin, skinwrinkles from sun damage, and a skin condition that causes redness on the face (rosacea), but there is no good scientific evidence to support these uses.

How does it work ?

Kinetin prevents green plant leaves from turning brown. There is some information that suggests kinetin might prevent age-related changes in human skin by protecting the DNA in skin cells from damage (antioxidant effects) and decreasing skin water loss

Uses & Effectiveness 

1.      Insufficient Evidence for

A skin condition that causes redness on the face (rosacea). Early research shows that applying a lotion containing kinetin helps to reduce most symptoms of rosacea, like roughness and redness, in most people. But it doesn't seem to help everyone.

Skin wrinkles from sun damage. Early research shows that applying a lotion containing kinetin to the face helps to reduce wrinkles and to improve the feeling of the skin in people who have wrinkled skin from the sun.

Aging skin.

2.      An inner ear disorder marked by dizziness, hearing loss, and ringing in the ear (Meniere disease).

3.      Skin imperfections.

Other conditions.

More evidence is needed to rate the effectiveness of kinetin for these uses

When taken by mouth: There isn't enough reliable information to know if kinetin is safe. It might cause side effects such as nausea, headache, diarrhea, rash, and ringing in the ears.
When applied to the skin: Kinetin is POSSIBLY SAFE when used in a cream or lotion containing kinetin 0.1% for up to 12 weeks. It might cause side effects such as redness, dryness, peeling, burning, stinging, and itching in some people. But it isn't clear if these symptoms are from kinetin or another ingredient in the products used.
When applied into the ear: There isn't enough reliable information to know if kinetin is safe or what the side effects might be.

Special Precautions and Warnings

Pregnancy and breast-feeding: There isn't enough reliable information to know if kinetin is safe to use when pregnant or breast-feeding. Stay on the safe side and avoid use.
Bleeding disorders: There is some concern that kinetin might prolong bleeding time and increase the risk of bruising and bleeding in some people with bleeding disorders. If you have a bleeding disorder, use kinetin with caution.
Surgery: Kinetin might increase the risk of bleeding during and after surgery. Stop taking kinetin at least 2 weeks before a scheduled surgery.

FUNCTION OF KINETINS

1.      It control cell division

2.      It can stimulate the development of roots

3.      It slow down aging of plant part

4.      It can break dormancy of buds leading to bud growth

5.      Kit stimulate mitosis in meristems and in embryos during germination

6.      It increase the reisitance of some plant to harmful effects scuh as viral infection, radiation and low temperature

7.      It promote axilary bud growth in plant

ETHYLENE is a group of plant growth regulators which are widely used for ripening fruits and for the production of more flowers and fruits. Ethylene is a small hydrocarbon, the colourless flammable gas which is denoted by a formula C₂H₄ or H₂C=CH₂. Ethene is the IUPAC name for ethylene.

FUNCTION OF ETHYLEN OR ETHENE GAS

It rtards lateral bud development

It hastens the ripening of fruits

It inhibit stem enlongation

It accelerate abscission of leaves, flowers and fruits

It accelerate aging of plant organs

 

 

DIFFERENCES BETWEEN VITAMINS AND HOMONES

One vitamin, Vitamin D, or cholecalciferol, is a hormone: it is made in the skin on exposure to sun and then interacts with a receptor in intestinal cells to induce synthesis of calcium binding protein. But the other vitamins are enzyme cofactors. The main difference is that vitamins participate chemically in specific enzymatic reactions whereas hormones are simply signals that are either bound to a receptor or not. Both vitamins and hormones are effective in very small amounts and do not supply calories.”

Maybe some elaboration would help, using a simple example. Vitamin B3, nicotinamide, is converted to the enzyme cofactor, NAD+. It binds to enzymes and participate in chemical reactions called hydride transfers. It is changed to NADH in the process. Example:

lactate + NAD+ <=> pyruvate + NADH.

From a chemist’s point of view, NAD+ is an oxidizing reagent, and NADH is reducing reagent.

NADH is recycled by the electron transport chain back to NAD+, which why we only need small amounts of the vitamin.

A hormone such as insulin does not undergo any chemical changes. It would be classified as a signalling molecule. It binds to a receptor, causing a conformation change that initiates a signalling cascade. The result is numerous chemical reactions downstream, but insulin itself never changes. It binds to a receptor and dissociates again, in dynamic equilibrium, able to bind to another receptor.

Hormones and vitamins differ in many other ways, but this is the key difference in terms of how they function.

Unlike plant hormones, animal hormones are often (though not always) produced in specialized hormone-synthesizing glands (shown below). The hormones are then secreted from the glands into the blood stream, where they are transported throughout the body. Some other differences include:

1.      Vitamins are synthesized in plants and taken by animals while hormones secreted mostly by endocrine glands and some by neurosecretory cells of animals

2.      Vitamins include esters, organic acids, etc. while hormones include water soluble amino acids and polypeptide or fat solublesteroids.

3.      Vitamins have ctatalytic properties and act as coenzyme while hormones excitatory and sometimes inhibitory but never act as coenzyme.

4.      Vitamins deficiency causes specific deficiency disease while hormones directly influence gene expressions.

ANIMAL HORMONES

Hormones which are sometimes called chemical messengers or organic substance are produced by duckless glands (endocrine glands)

There are many glands and hormones in different animal species, and we will focus on just a small collection of them.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Locations of endocrine glands in the human body. Image credit: OpenStax Anatomy and Physiology (2021).

In vertebrates, glands and hormones they produce include (note that the following list is not complete):

 

hypothalamus: integrates the endocrine and nervous systems; receives input from the body and other brain areas and initiates endocrine responses to environmental changes; synthesizes hormones which are stored in the posterior pituitary gland; also synthesizes and secretes regulatory hormones that control the endocrine cells in the anterior pituitary gland. Hormones produced include

1.      growth-hormone releasing hormone: stimulates release of growth hormone (GH) from the anterior pituitary

2.      corticotropin-releasing hormone: stimulates release of adrenocorticotropic hormone (ACTH) from the anterior pituitary

3.      thyrotropin-releasing hormone: stimulates release of thyroid-stimulating hormone (TSH) from the anterior pituitary

4.      gonadotropin-releasing hormone: stimulates release of follicle -stimulating hormone and luteinizing hormone from the anterior pituitary

5.      antidiuretic hormone (vasopressin): promotes reabsorption of water by kidneys; stored in posterior pituitary

6.      oxytocin: induces uterine contractions labor and milk release from mammary glands; stored in posterior pituitary

pituitary gland: the body’s master gland; located at the base of the brain and attached to the hypothalamus via a stalk called the pituitary stalk; has two distinct regions: the anterior portion of the pituitary gland is regulated by releasing or release-inhibiting hormones produced by the hypothalamus, and the posterior pituitary receives signals via neurosecretory cells to release hormones produced by the hypothalamus. Hormones produced (or secreted) by the gland include:

anterior pituitary: the following hormones are produced by the anterior pituitary and released in response to hormone signals from the hypothalamus

§  growth hormone: stimulates growth factors

§  adrenocorticotropic hormone (ACTH): simulates adrenal glands to secrete glucocorticoids such as cortisol

§  thyroid-stimulating hormone: stimulates thyroid gland to secrete thyroid hormones

§  follicle-stimulating hormone (FSH) and luteinizing hormone (LH): stimulates production of gametes and sex steroid hormones

§  prolactin: stimulates mammary gland growth and milk production

posterior pituitary: the following hormones are produced by the hypothalamus and stored in    the posterior pituitary

v  antidiuretic hormone: promotes reabsorption of water by kidneys; stored in posterior pituitary

v  oxytocin: induces uterine contractions during labor and milk release from mammary glands during suckling; stored in posterior pituitary

v  thyroid gland: butterfly-shaped gland located in the neck; regulated by the hypothalamus-pituitary axis; produces hormones involved in regulating metabolism and growth:

v  thyroxine (T₄) and triiodothyronine (T3): increase the basal metabolic rate, affect protein synthesis and other metabolic processes, help regulate long bone growth (synergy with growth hormone)

adrenal glands: two glands, each located on one kidney; consist of adrenal cortex (outer layer) and adrenal medulla (inner layer), which each produce different sets of hormones:

adrenal cortex:

mineralocorticoids, such as aldosterone: increases reabsorption of sodium by kidneys to regulate water balance

glucocorticoids, such as cortisol and related hormones: long-term stress response hormones that increase blood glucose levels by stimulating synthesis of glucose and gluconeogenesis (converting a non-carbohydrate to glucose) by liver cells; promote the release of fatty acids from adipose tissue

 

 

adrenal medulla:

epinephrine (adrenaline) and norepinephrine (noradrenaline): short-term stress response (“fight-or-flight”) hormones that increase heart rate, breathing rate, cardiac muscle contractions, blood pressure, and blood glucose levels; accelerate the breakdown of glucose in skeletal muscles and stored fats in adipose tissue; release of epinephrine and norepinephrine is stimulated directly by neural impulses from the sympathetic nervous system

pancreas: located between the stomach and the proximal portion of the small intestine; regulates blood glucose levels via the hormones:

insulin: decreases blood glucose levels by promoting uptake of glucose by liver and muscle cells and conversion to glycogen (a sugar storage molecule)

glucagon: increases blood glucose levels by promoting breakdown of glycogen and release of glucose from the liver and muscle

gonads: produce sex steroid hormones that promote development of secondary sex characteristics and regulation of gonad function:

ovaries (in females):

estradiol: regulates development and maintenance of ovarian and menstrual cycles

progesterone: prepares uterus for pregnancy

testes (in males): regulates development and maintenance of sperm production

The hormones produced and/or stored by the pituitary gland are summarized here:

Hormonal Regulation of Body Processes in Animals

The information below was adapted from OpenStax Biology 37.3

Hormones have a wide range of effects and modulate many different body processes. The key regulatory processes that will be examined here are those affecting blood glucose, hunger, metamorphosis, stress, and sex. We will primarily focus on these processes in vertebrates, but will also consider invertebrates in some cases.

Blood Glucose

Glucose is the primary energy source for most animal cells, and it is distributed throughout the body via the blood stream. The ideal, or target, blood glucose concentration is about 90 mg/100 mL of blood, which equates to about 1 tsp of glucose per 6 quarts of blood. After a meal, carbohydrates are broken down during digestion and absorbed into the blood stream. The amount present following a meal is typically more than what the body needs at that moment, and so the extra glucose must be removed and stored for later use. The opposite phenomenon occurs following a period of fasting. Insulin and glucagon are the two hormones primarily responsible for maintaining appropriate blood glucose levels.

Insulin is produced by the beta cells of the pancreas, which are stimulated to release insulin as blood glucose levels rise (for example, after a meal is consumed). Insulin lowers blood glucose levels through several processes:

Ø  enhances the rate of glucose uptake and utilization by target cells, which use glucose for ATP production

Ø  stimulates the liver to convert glucose to glycogen, which is then stored by cells for later use

Ø  increases glucose transport into certain cells, such as muscle cells and the liver

Ø  stimulates the conversion of glucose to fat in adipocytes and the synthesis of proteins.

These actions together cause cause blood glucose concentrations to fall, called a hypoglycemic ‘low sugar’ effect, which inhibits further insulin release from beta cells through a negative feedback loop.

When blood glucose levels decline below normal levels, for example between meals or when glucose is utilized rapidly during exercise, the hormone glucagon is released from the alpha cells of the pancreas. Glucagon raises blood glucose levels, eliciting what is called a hyperglycemic effect through several mechanisms:

Ø  stimulates the breakdown and release of glucose from glycogen in skeletal muscle cells and liver cells

Ø  stimulates absorption of amino acids from the blood by the liver, which then converts them to glucose

Ø  stimulates adipose cells to release fatty acids into the blood

Glucose can then be utilized as energy by muscle cells and released into circulation by the liver cells. These actions mediated by glucagon result in an increase in blood glucose levels to normal homeostatic levels. Rising blood glucose levels inhibit further glucagon release by the pancreas via a negative feedback mechanism. In this way, insulin and glucagon work together to maintain homeostatic glucose levels, as shown in below. Growth and Metamorphosis

In vertebrate species that undergo metamorphosis, such as amphibians, surges of T₃ are responsible for initiating development of new structures, reorganization of  internal organ systems, and other processes that occur during metamorphosis. In insects, metamorphosis is controlled by a set of hormones that determine whether the animal grows into the next larval stage or changes into an adult as it gets larger. The corpus allatum, an endocrine gland in the brain, secretes a hormone called juvenile hormone during all larval stages, which maintains the larval status of the animal. As the larvae grows, another endocrine gland in the brain releases prothoracicotropic hormone, which signals to the prothoracic gland to release the hormone ecdysone. Ecdysone promotes either molting (shedding the exoskeleton) or metamorphosis, depending on the level of juvenile hormone. Ecdysone in combination with high juvenile hormone results in molting into the next larval stage; ecdysone in combination with low juvenile hormone results in metamorphosis into an adult.

Stress: Short vs Long Term Responses

One of the main functions of endocrine hormones is to ensure the body’s internal environment remains stable (homeostasis). Stressors are stimuli that disrupt homeostasis. Some stressors require immediate attention and activate the short term, “fight-or-flight” stress response, which stimulates an increase in energy levels through increased blood glucose levels. This prepares the body for physical activity that may be required to respond to stress: to either fight for survival or to flee from danger. The fight-or-flight response exists in some form in all vertebrates.

In contrast, some stresses, such as illness or injury, can last for a long time. Glycogen reserves, which provide energy in the short-term response to stress, are exhausted after several hours and cannot meet long-term energy needs. If glycogen reserves were the only energy source available, neural functioning could not be maintained once the reserves became depleted due to the nervous system’s high requirement for glucose. In this situation, the body has evolved a response to counter long-term stress through the actions of the glucocorticoids, which ensure that long-term energy requirements can be met. The glucocorticoids mobilize lipid and protein reserves, stimulate gluconeogenesis, conserve glucose for use by neural tissue, and stimulate the conservation of salts and water.

The sympathetic nervous system regulates the stress response via the hypothalamus. Stressful stimuli cause the hypothalamus to signal the adrenal medulla (which mediates short-term stress responses) via nerve impulses, and the adrenal cortex, which mediates long-term stress responses, via the hormone adrenocorticotropic hormone (ACTH), which is produced by the anterior pituitary.

Short-term Stress Response

When presented with a stressful situation, the body responds by calling for the release of hormones that provide a burst of energy. The hormones epinephrine (also known as adrenaline) and norepinephrine (also known as noradrenaline) are released by the adrenal medulla. These two hormones prepare the body for a burst of energy in the following ways:

cause glycogen to be broken down into glucose and released from liver and muscle cells

increase blood pressure

increase breathing rate

increase metabolic rate

change blood flow patterns, leading to increased blood flow to skeletal muscles, heart, and brain; and decreased blood flow to digestive system, skin, and kidneys

Long-term stress response differs substantially from short-term stress response. The body cannot sustain the bursts of energy mediated by epinephrine and norepinephrine for long times. Instead, other hormones come into play. In a long-term stress response, the hypothalamus triggers the release of ACTH from the anterior pituitary gland. The adrenal cortex is stimulated by ACTH to release steroid hormones called corticosteroids. The two main corticosteroids are glucocorticoids such as cortisol, and mineralocorticoids such as aldosterone. These hormones mediate the long-term stress response in the following ways:

glucocorticoids:

promote breakdown of fat into fatty acids in the adipose tissue and release into bloodstream for ATP production

stimulate glucose synthesis from fats and proteins to increase blood glucose levels

inhibit immune function to conserve energy

mineralcorticoids:

promote retention of sodium ions and water by kidneys

increase blood pressure and volume (via sodium/water retention)

Coticosteriods are under control of a negative feedback loop (illustrated below), which can become mis-regulated in cases of chronic long-term stress.

 

CONCLUSION

Hormones olays vital roles in the development of both plants and animals. Over secretion and under secretion of these hormone can lead to abnormalities

 

 

 

 

 

 

 

 

 

 

 

 

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