Module 4 Flashcards
Hormones play a huge role in ________.
Digestive
What is the number one killer to hormones?
Stress
The nervous system is built for speed, it uses nerve impulses to prod the muscles and glands into immediate action so that rapid adjustments can be made in response to changes occurring both inside and outside the body. On the other hand what does the endocrine system do?
It moves slowly and uses chemical messengers called hormones, which are released into the blood to be transported leisurely throughout the body.
Although hormones have widespread and varied effects, the major processes controlled by hormones are:
Reproductions, growth and development, mobilizing body defences against stressors, maintain electrolyte, water and nutrient balance of blood, regulating metabolism and energy balance.
The endocrine system regulates processes that go on for _____ ____ _______ and, in some cases ___________.
Relatively long periods, continuously
What may hormones be defined as?
A chemical substance secreted by cells into the extracellular fluids, that regulate the metabolic activity of other cells in the body.
Although many different hormones are produced, nearly all of them can be classified chemicallas as either _____ ___-____ _____ (including _______, _______, and ______) or ________.
Amino Acid-Base Molecule (protiens, peptides and amines) steroids.
If we consider the local hormones called prostaglandins we must add a third chemical class why?
Because the prostaglandins are made from highly active lipids found in the cells of plasma membranes.
Where do steroids come from?
Made by the gonads and the hormones produced by the adrenal cortex.
What needs to be in order for a target cells to respond to a hormone?
Specific protein receptors must be present on its plasma membrane or in its interior, to which that hormone can attach.
Only when binding occurs, can the hormone influence the workings of a cell. True or False
True
What do hormones do to the body? Think Greek
They arouse or bring about their effects on the body’s cells primarily by altering cellular activity, by increasing or decreasing the rate of a stimulating a new one.
The precise changes that follow hormone binding depend on the specific hormone and the target cell type, buy typically one or more of the following occurs:
- Changes in the plasma membrane permeability or electrical state
- Synthesis of proteins or certain regulatory molecules (such as enzymes) in the cell.
- Activation or inactivation of enzymes
- Stimulation or mitosis
Despite the huge variety of hormones, there are really only two mechanisms by which hormones trigger changes in cells are?
Steroidal hormones and non-steroidal hormones
Steroidal hormones, being lipid-soluble molecules, the steroid hormones can do 6 things:
- Diffuse though the plasma membranes of their target cells.
- Once inside the steroid hormone enters the nucleus.
- Binds to a specific receptor protein there.
- The hormone receptor complex then binds to specific sites on the cell’s DNA
- Then activating certain genes to transcribe mRNA (messenger RNA).
- The mRNA is translated in the cytoplasm, resulting in the synthesis of new proteins.
Non-steroidal hormones, protein and peptide hormones, are unable to enter the target cells and instead bind to receptors situated on the target cell’s plasma membrane. How does this happen? 4 spets.
- The hormone binds to the membrane receptor
- Setting off a series of reactions that activates an enzyme.
- The enzyme, in turn, catalyzes a reaction that produces a second messenger molecule.
- That oversees additional intracellular changes that promote the typical response of the target cell to the hormone.
What prompts the endocrine system to release or not to release their hormones?
Negative Feedback Mechanisms.
What are negative feedback mechanisms?
The chief means of regulating blood levels of nearly all hormones.
In such systems, hormone secretion is triggered by some internal or external stimulus; then rising hormone levels inhibit further hormone release, even while doing what? And the result is?
Promoting responses in their target organs. As a result, blood levels of many hormones vary only within a very narrow range.
The stimuli that activate the endocrine system fall into three major categories, what are they?
Hormonal, Humoral and Neural
4 points of Hormonal
- is most common
- endocrine organs are prodded into action by other hormones
- hormones produced by the final target glands increase in the blood, they “feed back” inhibit the release of anterior pituitary hormones and thus their own release
- tend to be rhythmic, with hormone blood levels rising and falling again and again
2 points of Humoral
- changing blood levels of certain ions and nutrients stimulated humoral
- chemicals or elements in the blood that simulated the endocrine glands to function.
1 point of Neural
- this is isolated cases, nerve fibres stimulate hormone releases.
All though those three mechanisms (Hormonal, humoral and neural) typify most systems that control hormone release, they by no means explain all of them, and some endocrine organs respond to many different stimuli. True or False.
True
Name as many major endocrine organs as you can, there are 9.
Pituitary, thyroid, parathyroid, adrenal, pinal, thymus glands, pancreas, gonads, hypothalamus.
Why is the hypothalamus, which is part of the nervous system, also recognized as a major endocrine organ?
Because it produces several hormones.
Although the function of some hormone-producing glands (the ____ _____, ________, _______, and __________) is purely endocrine, the function of others (______ and _______) is mixed, both endocrine and exocrine.
The anterior pituitary, thyroid, adrenals and parathyroid. Pancreas and gonads.
Both types of glands are formed from epithelial tissue, but the endocrine glands are ______ glands that produce ________ that they release into the blood or lymph.
Ductless, hormones
Where is the hypothalamus located?
The hypothalamus is a small area in the ventral diencephalon of the forebrain, in the floor of the third ventricle, and is a functional link between the nervous and endocrine system.
How does the hypothalamus control most of the endocrine glands within the body?
Largely through stimulation of the pituitary gland by secretion of neurohormones.
What is a vital regulator of homeostasis, including the thermoregulation?
Hypothalamus.
What are thermoreceptors?
Neurons in the anterior hypothalamus respond to heat by initiating peripheral vasodilation and sweating.
How do neurons in the posterior hypothalamus respond to cold?
By initiating shivering, piloerection (goosebumps) and peripheral vasoconstriction.
What are osmoreceptors?
These receptors respond to an increase in blood osmolarity by releasing Antidiuretic Hormone (ADH) from the supraoptic nucleus which is then secreted by the posterior pituitary and acts to retain water at the kidneys.
What is another thing the osmoreceptors do?
It also stimulates neurons in the thirst centre in the lateral hypothalamus in an attempt to increase water intake.
What does leptin cause?
Satiety
What does ghrelin stimulate?
Appetite
Hypothalamus What are some indirect inputs from the bloodstream include information about?
Temperature, osmotic pressure, hormone concentrations
Hypothalamus What are some indirect nerual inputs?
Uses visceral and somatic sensory neurons, the limbic system and the reticular activating system
Hypothalamus Output: Biological Clock
Light sensed by retina causes stimulation of neurons leading the suprachiasmatic nucleus which stimulates the Pineal gland as a result.
Hypothalamus Output Secretory Neurons
ADH and Oxytocin are released by the supraoptic and paraventricular nuclei cell bodies. The axons descend into the posterior pituitary gland, where they terminate in blood vessels releasing the hormone directly into circulation. Thus the posterior pituitary acts as a storage site and is not a true endocrine gland.
Hypothalamus Outputs Hypothalamic hormones
The hypothalamus releases hormones which have an activating or inhibitory effect on their target organ, hence they are named releasing or inhibitory hormones respectively.
What are some releasing hormones from the hypothalamus? There are five.
Thyrotropin Releasing Hormone (TRH) Growth Hormone Releasing Hormone (GH-RH) Gonadotropin Releasing Hormone (GnRH) Corticotrophin Releasing Hormone (CRH) Prolactin Releasing Hormone (PRL-RH)
What are some inhibitory hormones from the hypothalamus? There are three.
Growth Hormone Inhibiting Hormone aka Somatostatin (GH-IH)
Gonadotrophin Inhibiting Hormone (GnIH)
Dopamine (PRL-IH)
Where does the pituitary gland aka hypophysis sit?
It is elongated appendage of the brain lying within a bony cavity of the sphenoid bone in the base of the skull.
Where does the pituitary gland sit compared to the hypothalamus?
The hypophysis is suspended ventral to the hypothalamus by a thin infundibular stalk.
How is the pituitary gland divided?
It is divided into anterior and posterior, with different embryological origins reflecting a difference in function.
What is the anterior and the posterior gland made of?
Anterior is glandular tissue and posterior nervous tissue.
There are several anterior pituitary hormones that affect many body organs. Tell me six of them.
Two of the six - growth hormone and prolactin- exert their major effects on non-endocrine targets. The remaining four thyrotropic hormone, adrenocorticotropic hormone, and the two gonadotropic hormones are all tropic hormones.
What do tropic hormones do?
They stimulate their target organs, which are also endocrine glands, to secrete their hormones, which in turn exert their effects on other body organs and tissues.
All anterior hormones:
1) are proteins (or peptides)
2) act through second-messenger systems
3) are regulated by hormonal stimuli and, in most cases, negative feedback
Growth Hormone (GH) General Metabolic Hormone
Its major effects are directed to the growth of skeletal muscles and long bones of the body, and thus plays an important role in determining final body size. Also a polypeptide hormone
GH is a protein-sparing and anabolic hormone that causes amino acids to be built into proteins and stimulates most target cells to grow in size and divide. At the same time, it causes _____ to be broken down and used for energy, and spares ________, helping to maintain blood sugar homeostasis.
Fat, glucose
Prolactin (PRL)
Is a protein hormone structurally similar to GH. Its only target is the breast. (pro = for; lact = milk). After birthing, it stimulates and maintains milk production by the mother’s breasts. Its function in males is not known.
Adrenocorticortropic hormone (ACTH) KNOW
Polypeptide hormone made in the pituitary gland. It regulates the activity of part of the adrenal cortex, the production site of important steroid hormones that affect electrolyte and water balance and the metabolism of fats, carbohydrates and proteins.
ACTH is found in vertebrates except for _____ ____, in mammals it contains ___ ________ ____.
jawless fish, 39 amino acids
Overproduction of ACTH is one cause of ______ _______.
Cushing syndrome.
What does T3 and T4 stand for?
Triiodothyronine and thyroxine
T3 and T4: effects on ___ _____ ______ and ______ ___ ______
ALL body systems and stages of life
T3 and T4: development where thyroid hormones are vital during the ____ period and the ____ ___ ____ ______ ______
fetal, and first few months after birth
T3 and T4: also promotes ______, enhances _____ _____ uptake by tissues and enzymatic system involved in protein synthesis. Thus promoting ____ _____.
Growth, amino acid, bone growth
T3 and T4: results in increase _____ ____, increased _____ _________.
Heat production, oxygen consumption.
T3 and T4: helping in metabolic actions such as ____________ ________, as thyroid hormones stimulate glucose uptake, glycogenolysis, gluconeogensis. In fat metabolism they mobilise lipids from adipose stores and accelerate oxidation of lipids to produce _____ (occurs within _________) as well as increasing size and number of ___________.
Carbohydrate metabolism, energy, mitochondria, mitochondria
Thyroid hormones also increase basal metabolic rate (BMR) in all tissues except Brain, spleen and gonads. True or False
True
Some thyroid hormones that have a _________ ________ are to increase cardiac output, heart rate and contractility.
Cardiovascular action
How do the thyroid hormones affect the respiratory system indirectly?
By increasing BMR causing increased demand for oxygen and increased excretion of carbon dioxide.
In the nervous system what are thyroid hormones required for?
They are required for myelination of neurons during development. They also enhance the sympathetic N.S. by increasing epinephrine receptors.
Reproductive system is affected by reduced levels of thyroid hormones by causing?
Irregular cycles and decreased libido.
In the alimentary system thyroid hormones increases ______ and ______ ____, _______ of _______ ______ and increases _______.
Appetite, feed intake, secretion of pancreatic enzymes and motility.
Thyroid - Stimulating Hormone (TSH) or Thyrotropic hormone influences the _____ and ________ of the thyroid gland to release ______.
Growth and activity, thyroxine
The release of thyrotropin is triggered by the action of thyrotropin-releasing factor (TRF), a substance found in the:
Hypothalamus of the brain.
What happens if there is not enough iodine available in the diet?
There is not enough thyroxine to be made and it will shut off the release of thyrotropin.
TRF, once released from the hypothalamus, it travels in the __________ to the anterior pituitary, where it causes the release of _______. This latter substance, a ________, is carried to the thyroid gland by the blood, where it stimulates the uptake of ____, the conversion of _________ to ________, and the secretion of _________ _____ into the bloodstream.
bloodstream, thyrotropin, glycoprotein, iodine, diiodotyrosine to thyroxine, thyroid hormones
Thyroxine inhibits the further release of __________ by interfering with the action of TRF; thus levels of thyroid hormones are regulated.
Thyrotropin
Gonadotropic hormones regulate the hormonal activity of the ____.
Gonads
In mares, follicle stimulating hormone (FSH) stimulates follicle development in the ______. As the follicles mature, they produce _______, and eggs are readied for _______.
ovaries, estrogen, ovulation
In males FSH stimulates _________ ___________ by the ______.
sperm development, testes
Luteinizing Hormone (LH) triggers ______ of an egg from the female ovary and caues the ruptured follicle to become a _______ ____.
ovulation, corpus luteum
LH then stimulates the corpus luteum to produce _________ and some _________.
Progesteron, estrogen
In males LH is also referred to as _______ _____-________ _______ (_____) called this because it stimulates testosterone production by the interstitial cells of the testes.
interstitial cell-stimulating hormone (ICSH)
Hormones of the posterior pituitary, is not an _________ gland in the strict sense because it does not make the peptide hormones it releases and it simply acts as a storage area for hormones made by the __________ ________.
endocrine, hypothalamic neurons.
Oxytocin release in significant amounts only during ______ and in ______.
Childbirth and nursing
Oxytocin stimulates powerful contractions of uterine muscle during _____, _______ relations and when ______ _______. It also causes ______ _______ (______ ______).
labor, sexual, breast feeding, milk ejection, letdown reflex
Antidiuretic Hormone (ADH) is a polypeptide hormone secreted by the _______ ____ ______. Its principal action is to regulate the amount of ______ excreted by the ______.
posterior pituitary gland, water, kidneys
ADH, also known as _______, causes ______ to reabsorb water directly from the renal tubules, thus concentrating the _____ and _____ products in the liquid, which will eventually become _____.
vasopressin, kidneys, slats and waste, urine.
ADH secretion by the pituitary is regulated by neural connections from the ________, which is believed to monitor either the volume of blood passing through it or the concentration of water in the blood. ______ or _____ ____ will raise ADH secretion and water will be retained.
hypothalamus, dehydration or body stress
Despite its insignificant size, the anterior pituitary gland controls the activity of so many other endocrine glands that is has often been called the _____ ____ _______.
Master Endocrine Gland
Why is the anterior pituitary not as all powerful in its control as it might appear?
Because the release of each of its hormones is controlled by releasing and inhibiting hormones produced by the hypothalamus
The hypothalamus liberates these regulatory hormones for the posterior pituitary into the blood of the portal circulation, which connects the blood supply of the hypothalamus with that of the posterior pituitary. True or False
False anterior
What are the two additional hormones the hypothalamus makes and how are they transported?
Oxytocin and antidiuretic hormone, which are transported along the axons of the hypothalamic neuro-secretory cells to the posterior pituitary for storage. They are later released into the blood in response to nerve impulses from the hypothalamus.
Where is the thyroid gland located?
Lies in the neck, in front of the upper part of the trachea
Where are the parathyroid glands located?
They are located dorsally to or within the thyroid gland itself.
What are the two hormones the thyroid makes?
Thyroid hormone and calcitonin.
What is the thyroid hormone referred to as?
The body’s major metabolic hormone
The thyroid hormone is actually two active iodine containing hormones which are?
T4 thyroxine and T3 triiodothryonine
The thyroid hormone regulates the basal metabolic rate and is important in the regulation of ______ of ______, particularly ____ _____. Release stimulated by the TSH from the pituitary,
growth of tissues, nervous tissue
Calcitonin regulates _____ _____ _____ along with the parathyroid hormone and acts to reduce _____ ____ by inhibiting its removal from bone.
blood calcium levels, blood calcium
Thyroid Hormone controls the rate at which glucose is burned, or oxidized and converted to body heat and chemical energy. Since all body cells depend on a continuous supply of chemical energy to power their activities, meaning?
Every cell in the body is a target.
Thyroid Hormone is also important for ____ ____ _____ and _______, especially in the _______ and ________ _______.
normal tissue growth and development, reproductive and nervous system
Thyroid hormones are lipid soluble, thus need a transporting protien in order to travel in the blood. True or False
True
Half-life in the blood is _ day(s) for T3, _ day(s) for T4.
1, 6
How much percentage is the thyroid hormones in circulation are bound?
99%
What is the primary transport protein for thyroid hormones?
Thyroid binding globulin (TBG), which is synthesized in the liver, this protein bind 70-80% of the circulating thyroid hormones.
What is the remainder of thyroid hormones carried by?
Thyroxine-binding pre-albumin or albumin.
Only free T3 and T4 can enter cells to exert their actions. T4 is de-iodinated to T3 in many cells of the body, particularly the _____ and ______.
Liver and kidneys
The thyroid secretes 90% T4, with 50% of this being de-iodinated to T3. The remainder is converted to reserve T3 (rT3). This is an inactive form of T3 and so creation of its regulatory mechanism. More rT3 is created when the body needs to? Then what happens to them?
Reduce the action of T3 and T4. The hormones are further de-iodinated to diiodothyronine and mono-iodothyronine in the liver and kidneys. Iodine is recycled or excreted in the urine.
What does calcitonin or thyrocalcitonin do?
Decreases blood calcium levels by causing calcium to be deposited in the bones.
Calcitonin acts antagonistically to which hormone?
Parathyroid hormone.
Whereas thyroxine is made and stored in follicles before it is released in the blood calcitonin is made by?
Made by the so called C cells found i the connective tissue between the follicles. It is released directly to the blood in response to increasing levels of blood calcitonin production is meager to ceases in elderly adults.
How many parathyroid glands are there?
Generally four
In the horse, there are ‘nests’ of _____ ______ along the neck to the thoracic inlet.
parathyroid tissue
What does ganglion mean?
Nerves
What is an important regulator of calcium ion homeostasis for the blood?
Parathyroid Hormone
What happens when blood calcium levels drop below a certain level?
The PTH will stimulate bone destruction and release calcium into the blood
PTH is a hyper calcemic hormone (that is, it acts to increase hypo calcemic hormone. Which is the hypo calcemic hormone?
Calcitonin.
What happens when blood calcium levels fall too low?
Neurons become extremely irritable and overactive. They deliver impulses to the muscles at such a rapid rate that the muscles go into uncontrollable spasms, which may be fatal.
Where are the adrenal glands located?
They lay cranial to the kidneys within the retroperitoneal space.
Adrenal glands consist of two layers what are they?
Cortex and medulla.
The adrenal cortex is red to light brown in colour and is composed of three zones. From the outer to the inner, the layers are?
- zona glomerulosa
- zona fasciculata
- zona reticularis
The adrenal cortex produce hormones derived from __________, which is abundant in the cells. The adrenal cortex represents ___-____% of the adrenal gland.
cholesterol, 80-90%
What is the adrenal medulla primarily involved in?
Production of catecholamines; epinephrine and norepinephrine
In fetal life, which part of the adrenal plays a role in the automatic nervous system?
Medulla
The adrenal medulla acts as a ____ _____ with the _________ ____ ______ _____.
sympathetic ganglion, postganglionic cells lacking axons
Mineralocorticoids is mainly _________ and is produced by the _____ ____ adrenal cortex cell layer.
aldosterone, outer most
What does Mineralocorticoids do and where do they target?
Regulate the mineral and salt content of the blood, particularly the concentrations of sodium and potassium ions. They target kidney tubules that selectively reabsorb the minerals.
Whats another name for glucocorticoid?
Cortisone or cortisol
Where is glucocorticoid made and what does it do?
In the middle cortical layer and promotes normal cell metabolism and helps the body to resist long-term stressors, primarily by increasing blood glucose levels.
When blood levels of glucocorticoids are high, fats and even proteins are broken down by body cells and converted to glucose, which is released in the blood. True or False
True
Cortisone seems to control the more unpleasant effects of inflammation by decreasing edema. True or False
True
Cortisol is released from the adrenal cortex in response to rising blood levels of PTH. True or False
False ACTH
Androgen
Male sex hormones, androstenodione
Catecholamines
adrenaline, the fight or flight
An environmental or internal stimuli (such as stress or light regulating the circadian rhythm) causes the hypothalamus to release:
ACTH-releasing hormone (ACTH-RH)
ACTH-RH flows to the pituitary gland, where it stimulates the production of which hormone?
Adrenocorticotropic Hormone (ACTH)
Cortisol has a permissive action which means?
Without cortisol certain chemical reactions within cells are unable to occur, for example the production of epinephrine and glucagon.
Cortisol is a stress hormone, in times of stress it is released and enhances the effect of ____________ on blood pressure.
Norepinephrine
Cortisol is also essential for the day to day maintenance of normal blood pressure and will also stimulate ____________ and inhibit certain tissues utilization of glucose.
gluconeogenesis
Cortisol stimulates the degradation of ____ and ______ and inhibits ____ _____ in some tissues. Along with this degradation of ____, results in a growth-inhibiting effect in times of stress.
fats and proteins, DNA synthesis, proteins
Cortisol has anti-inflammatory effects. True or False
True
Cortisol inhibits the formation of prostaglandins and cytokines and reduces the ability of WBC being transported to an injured area. True or False
True
Cortisol helps keep in check inflammatory processes that could potentially cause tissue damage. True or False
True
Cortisol is also ____________, by reducing the lymphocyte numbers in circulation and reducing antibody production.
immunosuppressive
What is a common factor between the adrenal medulla and the posterior pituitary?
Develops from a knot of nervous tissue.
When the adrenal medulla is stimulated by sympathetic nervous system neurons, its cell releases two similar hormones?
Epinephrine also called adrenaline and norepinephrine into the bloodstream
What are epinephrine and norepinephrine referred to as?
Catecholamines.
Why is the adrenal medulla often thought of as a misplaced sympathetic nervous system ganglion?
Because some sympathetic neurons also release norepinephrine as a neurotransmitter.
What happens when the adrenal medulla releases its hormones into the blood stream?
The catecholamines increase heart heart, blood pressure, and blood glucose levels and dilate the small passageways of the lungs.
When catecolamines are released what are the events result?
These events result in more oxygen and glucose in the blood and faster circulation of blood to the body organs (most importantly to the brain, muscles and heart).
Whats the difference between catecolamines and glucocorticoids?
Catecolamines, produced by the adrenal medulla, prepare the body to cope with a brief or short term stressful situation and cause the so-called alarm stage of the stress response. Glucocorticoids are produced by the adrenal cortex and are more important in helping the body to cope with prolonged or continuing stressors.
Glucocorticoids operate primarily during the resistance stage of the stress response, what happens when they are successful and when they aren’t?
If they are successful in protecting the body, the problem will eventually be resolved without lasting damage to the body. When the stress continues on and on, the adrenal cortex may simply “burnout” which is usually fatal.
Brain damage can/will occur if stress takes forever and it will never go back down. Many studies have proven this. So what does high stress burn?
High stress burns sugars which leads to high sugar levels.
Where is the pineal gland found?
The pineal gland is small and cone shaped and found in the roof of the third ventricle of the brain.
Even though there is little known about the pineal gland what can you tell me about it?
Only the hormone melatonin appears to be secreted in substantial amounts, the levels rise and fall during the course of the day and night. Peak levels are found at night and make us drowsy. In some animals, melatonin also helps regulate mating behaviour and rhythms.
Where is the thymus found?
Found cranial to the heart and has a lobular structure. Within the lobules the tissue consists of an outer cortex and an inner medulla.
What time frame is the thymus large?
Large in infants and children, decreases in size throughout adulthood
What hormone comes from the thymus?
Thymosin.
The thymus is not important in the immune response. True or False
False it is
The thymus acts as a incubator for the maturation of a special group of WBCs, what are they?
T lymphocytes.
The pancreas is a __________ _____ and has _________ and __________ tissues.
tubuloalveolar gland, exocrine and endocrine
The _________ of the pancreas is the larger of the two parts and secretes __________ _______.
exocrine, pancreatic juice
What is pancreatic juice and where does it drain into?
A solution containing enzymes for carbohydrate, protein and triacylglycerol digestion. Pancreatic juice drains into the small intestine where it is functional.
The _________ of the pancreas secretes hormones for the regulation of blood glucose concentration, including ______, ________ and __________.
endocrine, insulin, glucagon and somatostatin
Where is the pancreas located and what three parts can it be divided into?
The pancreas is located in the craniodorsal part of the abdomen in close association with the duodenum. It can be divided into a body, and the left and right lobes.
Generally where does the portal vein run by the pancreas?
Between the left and right lobes.
The functional units of the pancreas’s endocrine part are the?
Islets of Langerhans
The lobes of the pancreas are loosely united by interlobular connective tissue. Connective tissue contains blood vessels, nerves and lymphatics. True or False
True
The pancreatic duct is the biggest of the two and opens into the duodenum with the bile duct at the major duodenal papilla. True or False
True
Where does the accessory duct of the pancreas open?
It opens on the opposite aspect of the duodenum at the minor duodenal papilla.
The pancreas lies mainly on the left, in the very ventral part of the abdomen. It is square in shape and lies within the sigmoid flexure of the duodenum. True or False
False. The pancreas lies mainly on the right, in the very dorsal part of the abdomen. It is triangular in shape and lies within the sigmoid flexure of the duodenum.
Where is the ventral surface of the pancreas?
Is directly attached to the right dorsal colon and base of the caecum.
Where is the dorsal surface of the pancreas?
Directly attached to the right kidney and liver.
The portal vein perforates the pancreas at the pancreatic ring. True or False
True
Both the _________ and __________ ducts persist throughout development.
pancreatic and accesory
There is a constant secretion of pancreatic juice, which increases after feeding. Why does it maintain a stable environment important for microbe survival in the colon and caecum?
It provides the colon and caecum with a constant supply of buffered solution.
What is the exocrine (enzyme producing) part of the pancreas?
Pancreatic Islets or Langerhans
More than a million islets separated by exocrine cells, each of these tiny clumps of cells goes busily about their business manufacturing its hormones and working like an organ within an organ. True or False
True
Two important hormones produced by the islet cells are? And what do they both do?
Insulin and glucagon. Both help regulate the amount of sugar, glucose in the blood, but in opposite ways.
The islets only produce two hormones. True or False
False, they produce small amounts of other hormones just not as important as insulin and glucagon.
When does insulin get released?
When the body indicates there are high blood glucose levels.
Insulin acts on just about all body cells and increases their ability to transport _______ across their plasma membranes.
Glucose
Once glucose is inside a cell what does it do?
Glucose is oxidized for energy or converted to glycogen or fat for storage. These activities are also accelerated by insulin.
Since insulin sweeps the glucose out of the blood, its effect is said to be _________.
Hypoglycemic
As blood glucose levels fall, the stimulus for ________ release ends.
Insulin (another classic case of negative feedback control)
Many hormones have hyperglycemic effects, name some, and what is the only hormone that decreases blood glucose levels?
Glucagon, glucocorticoids, epinephrine, and insulin is the only one.
What happens when we do not have insulin?
Insulin is absolutely necessary for the use of glucose by the body cells, without it, essentially glucose cannot get into the cells to be used.
What does the female gonads or ovaries do?
They produce ova or eggs. Also produve two groups of steriod hormones estrogens and progesterone.
Tell me more about estrogen?
Produced by the graafian follicles of the ovaries. Works with progesterone to prepare the uterus to receive a fertilized egg. Also helps maintain pregnancy and prepare the breasts to produce milk.
Tell me more about progesterone
Acts with estrogen to bring about he menstrual cycle. During pregnancy it quiets the muscles of the uterus. Is produced by another glandular structure of the ovaries, the corpus luteum.
What are the hormones of the testes?
Produce male sex hormones or androgens of which testosterone is most important. Made by the interstitial cells of the testes, causes the development of the adult male sex characteristics.
What are other hormones of the gonads?
Gonadotropin releasing hormone (GnRH) Luteinising hormone (LH) Follicle stimulating hormone (FSH) Prolactin (PRL) Oxytocin (OT) Estradiol (E2) Progesterone (P4) Relaxin Placental Lactogen (PL) Prostaglandin
What does the mouth do?
Where chewing happens and the food gets ground up.
What muscles are involved with the mouth?
Plate 43, 44 & 47
Masseter, buccinator, sternothyroid, omohyoid, depresser, geniohyoid, oreicularis oris, tongue aka hyoglossae
In the interdental space the jaw bones are covered by a _____ _______ ______.
thin mucous tissue.
The 3 premolars and the 3 molars have the same ____ and ______.
anatomy and function
A horse may have a rudimentary premolar in front of the upper cheek teeth, known as a ___ _____.
Wolf Tooth
The muscles of mastication (chewing) are innervated by ___ __________.
NV Trigeminus
The muscles of the cheek are innervated by __ _______.
N Facial
The intrinsic and extrinsic muscles of the tongue are innervated by ___________. Also tell me more about the intrinsic and extrinsic mucsles.
Hypoglossal
Motoric intrinsic motions muscles, and extrinsic hyoid muscles - keeps tongue in balance. Page 81
Mastication is a reflex activity influenced by will. Tell me the process.
Presence of food excites taste and pressure sensors, which will start the chewing process. The chewing pressure is refectory, arranged through impulses from the teeth sensors. (every tooth is a sensor)
When the tongue is dry you know something is wrong. True or False
True
What is saliva secreted by?
Glandulae partois, glandulae sublingulaes (Fascial N), glandulae submandibulares, little buccal glands (trigeminal, glossopharyngeal, facial N)
Where are salivary glands present?
Cheek, tongue, lips, oeseophagus, soft palate and phargynx, but the major salivary glands are located further away from the oral cavity and function through connective ducts.
The amount of secreted saliva is related to the food substance. Give me two examples.
Dry Food: mainly serous saliva
Rough Food: mainly mucous saliva (for lubrication)
The glandula parotis only secretes serous saliva. The other two a mixture of serous-mucous saliva. True or False.
True
How long is the esophagus?
4-5 feet
In the esophagus there is a muscular ring, called the ______ ______, which connects the stomach to the esophagus.
Cardiac sphincter
What is mucosa?
contains mucous cells and the excretion ducts for the fluid from the digestive glands. (internal layer makes the secretion)
What is submucosa?
The connective tissue layer underneath the mucosa.
What are the 3 muscular layers of the stomach?
Circular, longitudinal and oblique
What is the serosa?
The surrounding tissue
The serosa also covers the mesenterium that contains all the blood vessels and nerve supply from and to the colon. (the blood vessels are not in the organ they are on top) True or False
True
What is amylase?
Carbohydrate digestion started in the mouth
What is acid?
bacteria extermination aka bacteria killer
What is pepsin?
divides the long protien chains into smaller amino acids, controlled by the vagus nerve
What is the cephalic phase?
Through excitation of nose and mouth sensors (brain-smell)
What is the gastric phase?
a) vago - vagal reflex: excitation of viscero sensoric fibers in the vagus nerve causes secretion.
b) local reflexes in the stomach wall
c) the hormone gastrin: excitation of the antrum pylori and the excitation of the mucosa of the antrum sets free gastrin.
Gastrin will be deported by the blood stream and never returns through the stomach arteries back to the stomach wall. True or False
False but returns
Gastrin activates the stomach secretion as well as the _____ secretion.
Pancreas
Gastrin is a polypeptide hormone secreted by certain cells of the pyloric glands, which strongly stimulates secretion of gastric acid and pepsin, and weakly stimulates secretion of pancreatic enzymes. True or False
True
Regulation of depletion of the stomach?
The locomotion of the stomach is controlled by the N. Vagus: afferenental impluses from the stomach run to the vagal nuclei in the brainstem.
The Locomotion of the stomach: Nervous
Increase of pressure; decreases the stomach locomotion through the plexus myenteric (gastroenteric reflex)
The Locomotion of the stomach: Hormonal
lipids in the duodenum are divided into glyceride and fatty acids. These trigger the release of the hormone enterogastrong (will decrease stomach locomotion) in the colon wall which reaches the stomach through the blood stream and decreases the stomach locomotion.
When there are no fats present in chyme, that means you have a leaky gut and the stomach will stay in constant motion. True or False
True
The Locomotion of the Stomach: Hunger Contractions:
Peristaltic waves of contractions caused by _________ N Vagus activity on an _______ stomach.
increased, empty
The Locomotion of the Stomach: Hunger Contractions:
Excitation of the vagal nerve increases the ___________ force but not the frequency of the ____________
contractions, contractions
The Locomotion of the Stomach: Hunger Contractions:
Through intramural reflexes (in the stomach wall), by mechanical excitation of the stomach wall (presence of food) and through excitation of the _____ of the __________ by the ____ _____ from the stomach, the ______ closes.
mucosa, duodenum, acidic chyme, pylorus
The Locomotion of the Stomach: Hunger Contractions:
The stomach can mix the content more. True or False
True
The Locomotion of the Stomach: Hunger Contractions:
The more dilated the contents of the stomach, the more full the contractions to empty the stomach are. True or False
True
On an average sized horse, the stomach has a capacity of around _ __ _____ (___) and works best when it contains about _ __ ______ (____).
4 US gallons (15L), 2 US gallons (7.6L)
Why is continuous foraging or several small feedings per day perferable to one or two large ones?
Because the stomach empties when 2/3 full, whether stomach enzymes have completed their processing of the food or not, and doing so prevents full digestion and proper utilization of feed.
The horse stomach consists of an ___-________ _____ _____ (saccus cecus), divided by a distinct border, the ______ ______, from the _______ ____ stomach.
non-glandular proximal region, margo plicatus, glandular distal
Where does chyme leave the stomach?
The pyloric valve, which controls the flow of food out of the stomach
Where is the stomach?
9th-14th rib on left side
What is the endoderm?
The endoderm is the inner layer forming the epithelia and glands. The layers around it are from the mesoderm forming the skeletal muscle, (oesophagus and anus), smooth muscle (from lateral plate mesoderm) and connective tissue
Where do parasites sit in the stomach?
The last region
Throughout the stomach it gets ______ and ______ when food passes through the regions.
slimier and thinner
The stomach wall is a fibrous map needing fat. True or False
True
The stretching of the atrium is the trigger to produce ________ ____ and at the same time makes the Vagal N to produce gastrine that goes around the stomach to pancreas into duodem then it produces NA2 CO3 (sodium bicardonate) which is a ________.
hydrocloric acid, buffer
When we are feeding pellets what happens?
By feeding pellets we are not stretching the stomach or duodem so we don’t trigger the vagal nerve then in turn don’t amke NA2CO3 to wash off the acid of the food coming from the stomach.
The intestinum tenue: The smaller intestines. What are they?
Duodenum, jejunum, ileum
The colon: The greater intestines
the caecum, colon acsendens, the colon transversum, the colon desendens, the rectum
How long is the duodenum?
1 meter or 3.2 feet
The duodenum starts at ____ ______ at the level of the stomach (pylorus) _____ ______, runs in a _ form caudal of the liver, to extend into ____ _________ _____.
pars cranialis, cone shaped, S, pars descendent duodeni
At the level of the pars cranial is there are two papilla duodeni, what are they?
Papilla duodeni major, pailla duodeni minor
What is the papilla duodeni minor also called? and its the entrance for what?
Papil of Vator, Sphincter of Oddi, also the entrance for the hepatic duct and pancreatic duct
Tell me about the descendent duodeni.
Runs lateral caudal to the right kidney and extends into the transvers duodeni, which sticks to the colon transversum (at the dorsal abdominal wall), and to the colon transversum at the caudal side)
Tell me more about the ascending duodeni.
Runs medial of the left kidney and extends into the jejunum (runs into the small intestine). This transition into the jejunum is marked by the free border of the plica duodenocolica (fold of the perineum)
Where does the duodenum receive blood from?
The coeliac artery and the crainial mesenteric artery, both are branches of the aorta.
The _______ _________ _____ drains blood from the duodenum into the portal vein. This blood, carrying the products of digestion, enters the _____.
cranial mesenteric vein, liver
What is the ligament that is very long that connects the stomach and angle of treitz, but Shantel has only found it in one horse where it was not scarred?
Ligament of treitz
How long is the jejunum?
25 metres or 80 feet
Tell me about the jejunum?
Mainly in the left flank, ventral of the pelvic entrance, left of the caecum, covered by the colon ascendants.
Where does the ileum start?
starts at the level of the plica iliocaecalis
How long is the ileum?
.5 meters or 1.6 feet
Where does the ileum end?
Ends between the corpus and basis of the caecum in the papilla ilialis (aka iliocaecal value)
How long does food stay in the caecum for?
2-5 days
What is the length of the caecum?
Length: basis, corpus, apex: 1 meter or 3.2 feet
How much food can the caecum take?
35Lt or 9.21 gallons
Localization of Caecum: basis caeci
dorsal under costal rib 18
Localization of Caecum: body caeci
ventral of pelvic entrance, to the ventral lateral abdominal wall to extend cranial into
Localization of Caecum: apex caeci
complete surrounded by colon ascendants
The caecum has four taeniae aka indents/groves, what are they
Taenia lateralis, medialis
Taenia dorsalis, ventralis
How long is the colon ascendens?
4 meter or 12 feet
How much food can the colon ascendens take?
80 liters or 21.05 gallons
Localization of the colon ascendens: from ostium caecocolicum (the part where it starts) following the space at intercostal 18 at the cranial side. True or False
True
Localization of the colon ascendens: starts as collum coli at the ____ _____ (the neck of the colon)
basis caeci
Localization of the colon ascendens: extends as colon ventral dextrum (_______) at the right side of the ribs to the diaphragm into the flexura (_ _______) diaphramatic ventralis or sternalis (_______ ___ _____ _____)
right, a curve, under the sternal bone
Localization of the colon ascendens: and from there into colon vertral sinsitrum (____) at the left side of the abdominal wall to extend through flexura pelvina (_____ _________) into colon dorsal sinsitrum which extends into the flexura diaphragmatica dorsalis to curve back into the colon dorsal dextrum.
left, pelvic curvature
The ascending colon aka colon __________, changes from right to left at the level of the 18th thoracic vertebra cranial to the artery mesenterial cranialis. (attached to the __________)
transversum, diaphragm
At this level the colon transversum is attached with the ______ and ________ _____ to the ______ ______ ____.
pancreas and transversa duodeni to the dorsal abdominal wall
Where does the rectum start?
It starts at the level of the entrance of the pelvic room, at the section where the artery mesenterial caudalis splits into the artery rectalis cranialis and artery colico sinistra.
How long is the rectum?
30 cm
Tell me the 3 bullets for the attachments of the intestines.
- starts from the cranial radix (root) mesentericum (below L1)
- attaches through a small meso (double layer of the peritoneum (fascia)) to the taenia dorsalis and ventralis of the colon ascend.
- start and end of the colon ascend, is connected to the radix mesentericum and the dorsal abdominal wall
What are the chemicals inside the small intestine?
HCl (hydrochloric acid)
NaC03 (sodium carbonate)
NaCl (sodium chloride) sait
H2CO3 (carbonic acid) a gas
The small intestine helps with further _____ and _______ that was started in the mouth.
resorption and digestion
What is pancreas lipase?
digestive of the lipoids (triglycerides)
Pancreas amylase is identical to what?
Identical to amylase in the saliva
What is trypsinogen activated by?
activated by trypsin under the influence of enteropeptidase from the mucosa of the duodenum
What is chymotrypsin gene and procarboxypepitdase activated by?
Activated by trypsine
What are zymogenes of the proteases activated by?
Inactive in the pancreas itself but activated by peptides in the intestines.
What in the stomach excites the pancreas?
Gastrine
Secretion starts through the ____ _____ excitation after nutrition is taken in.
Vagus Nerve
Excitation of the duodenal mucosa sets free three hormones from the duodenal wall, what are they?
Secretine: stimulates HCO3 (sodium bicarbonate) secretion
Pancreozymin: stimulated enzyme production in the pancreas
Choleystokinin: activated but chymus in duodenum releases the papilla duodenalis, so fall and pancreas fluid can enter duodenum.
Gall contains gall salts which will emulate the lipoids to increase the contact surface for _____ from the _______.
lipase from the pancreas
__________ excitation decreases pancreas secretion.
Sympathetic
Digestion processes in the small intestine: Carbonhydrate digestion
- Polysaccharides: starch and glycogen: broken down by pancreas amylase into maltose and gluocse
- disaccharides: maltose, saccharose, lactose (maltsugar, beetsugar, milksugar): broken down by maltase, saccharase and lactase into monosaccharides
Digestion processes in the small intestine: Lipoid digestion
- gall salts: emulate the lipoids into small particles to increase contact surface for lipase form the pancreas.
- lipase: breaks down the lipoids partially
a) so no in the small intestine there is a mixture of: triglycerides (non-digested), diglycerides, monoglycerides, glycerol and fatty acids.
b) the mono and diglycerides form molecule aggregations, so called mi-cells which can be absorbed in the lymphatic system
Digestion processes in the small intestine: protein digestion
- in the stomach the big protein chains are broken down into smaller chains by pepsin
- trypsin and chymotrypsin break down the rest of the polypeptides in the little peptide chains
- these little peptide chains will be broken down by enzymes in the wall of the intestines; for example amino peptidase, carboxypeptidase, dipeptidase, etc. At the end single amino acids will remain and be absorbed.
The locomotion of the intestine is activated by?
Vagus nerve and acetylcholine (an organic molecule that acts as a neurotransmitter)
The locomotion of the intestine is inhibited by?
adrenaline, over stretching of the intestine can cause the locomotion to stop completely!
The colon functions as deposit of the non digested food remnants, to dispose them after a while as feces. Also water will be absorbed here. True or False
True
The large intestine houses over _____ species of bacteria that perform a variety of function.s
700
Undigested polysaccharides (fiber) are metabolized to short-chain fatty acids by bacteria in the large intestine and absorbed by ______ ________.
passive diffusion
The bicarbonate that the large intestine secretes helps to _______ the increased ______ resulting from the formation of these fatty acids.
neutralize, acidity
Bacteria found in the colon also produce large amount of vitamins, such as? And what do they help with?
Vitamin K and Biotin (a B vitamin), for absorption into the blood
What dose the colon excrete?
- Ca, Mg, FeS, heavy metals
- non-digested food particles
- fermentation and decomposition products
- waste products from the fall like hemoglobin
- water and salt
When poop is putty like where is the problem likely?
Pancreas
What gives the color to manure?
Gall
What is the size of the liver?
1.5% of the body weight.
What is the localization of the liver?
Complete int he intra thoracal part of the abdominal space. So it is covered by the ribs but still in the diaphragm.
Liver on the left?
Lobus hepatis sinistra, intercostal ribs 6-10
Liver on the right?
Lobus hepatis quadratus and dextrum, intercostal ribs 6-15
The liver plays an important role as an interstation of the __________ ________ between the _________ _____ and the ______ _______ _______.
circulatory tract, digestive tract, venous blood circulation
All the blood of the digestive tract has to pass the liver through the _____ ______. Why is this important?
Veina Porta. This way the liver is capable of controlling the composition of the blood. Lover can report this to the hypothalamus.
Test Question: Liver and Lung relations
Vagal Nerve, Diaphragm, blood transfer, sympathetic activity. KEEP THINKING OF MORE, could it also be something like if we arent moving as much we arent breathing as much, so we have more old blood and also since we arent moving our organs aren’t moving?
When the horses poop is too dark what is going on?
Too much gall
Why can we connect the liver to the reproductive system?
The faliform ligament is attached to your belly button goes to your liver.
What is the ligament that connects the liver (from the diaphragmatic surface) to the diaphragm?
The coronary ligament.
