Endocrine System

______ is the means whereby neighboring cells in direct contact with each other, communicate by the exchange of ions and molecules, through gap junctions in the cell membrane; local type of communication acting over extremely small distances

Name 4 types of Communication

______ communication also occurs over small distances, but uses chemical messengers that are used to carry information from cell to cell within the same tissue; the concentrations of the the chemical messengers are so low that they do not affect neighboring tissues

What is it called when a specialized cell, the neuron, releases a neurotransmitter ver close to the target cell (the effector) at the synapse? effects are usually short lived

A ____ is defined as a chemical messenger released by a tissue which is carried in the circulation to reach specific target cells in other tissues around the body.

What are the 3 categories that hormones are classified into based on their structure?

What are some hormones derived from amino acids? these are from the former _________ of the pituitary.

Other hormones within the peptide hormone group that form from an amino acid chain with a carbohydrate attached?

Name 2 Glycoprotein based hormones

______ communication involves the release of hormones, produced by specialized endocrine cells, into the circulatroy system where they are carried to the target cells, tissues, or organs. The target cells, tissues or organs have specialized receptor sites to which the hormone must bind before it exerts its effects.

____ transmission of impulse where the membranes are fused to one another

Peptide hormones are formed from peptides or longer chains of amino acids. THose formed from short chains include:

Peptide hormones have longer chains and are classified as small proteins are:

What is the Antidiuretic Hormone (ADH) AKA

Hormones derived from lipids belong to one of two groups, those similar in structure to cholesterol are known as _____ hormones whereas those derived from the essential fatty acid arachidonic acid are called _____.

Name the 4 steroid hormones and what they are released by

____hormones differ from other hormones in that they are transported in the blood bound to _______ rather than free molecules; this causes them to remain in circulation longer than other hormones

______ act as improtant paracrine molecules, coordinating cellular activity and enzyme reactions in extracellular fluid.

Name the 3 Eicosanoids

The majority of hormones in the body are controlled by a _______ mechanism.

THe stimulus that triggers the secretion of hormones is usually one of the following:

Blood levels of most hormones operate through a negative feedback mechanism maintaining _____

As blood glucose levels ___ following a meal, the production of ____ is stimulated and the blood glucose results in a __ in the secretion of insulin from the ____.

2 organs known as "sweet breads"

The _____ is located beneath the thalamus of the brain and plays a critical role in controlling the release of many of the hormones within the body.

This secrets regulatory hormones that control the hormonal activity of the anterior pituitary, so affecting the activity of the thyroid gland, the cortex of adrenal gland and the reproductive organs.

The hypothalamus has _____ nervous control over the hormones secreted by the _____ of the adrenal glands, in addition to acting as an endocrine organ itself, releasing hormones into circulation via the _________.

The ______ and ________ work hand in hand to regulate many of the organs of the body and thus are often viewed as one even though they are not.

The pituitary gland or hypophysis can be considered into two parts, what are they?

For years their was an _______ of the pituitary identified seperately as one of the three lobes. The most recent nomenclature includes this in with the ______.

What are the 3 divisions of the Adenohypophysis(anterior lobe or anterior pituitary)

formed from a structure called Rathkes Pouch, a structure derived from the mucous membranes of the embryonic pharynx.

Originated from the embryonic brain, and in the adult, the posterior lobe is still connected to the brain by means of the pituitary stalk. This allows for the production of posterior pituitary hormones to be produced in the hypothalamus and be transported via nerves to the posterior lobe to be stored and later used as needed.

The posterior pituitary acts as a storage site for two hormones? 
These are both synthesized in the ______ by specialized secretory neurons and are stored in the posterior pituitary prior to release.

____ has effects on the kidneys, causing an increase in the absorption of water by the tubules. this reduces the volume of urine and increases the water retention and volume of blood.

causes contraction of the smooth muscle of the uterus during labor and stimulates milk production of "let down" at lactation.

is composed of epithelial cells and connective tissue separated by sinusoids of blood. This area has six types of cells that can be seen and differentiated.

precursor to cells that produce the hormones of the anterior lobe.

are separated on the basis of their staining properties which can be correlated to the hormones that they produce.

the 2 types of chromophils

2 Acidophils

4 Basophils

a series of veins that carry blood from the pituitary stalk and the brain to the adenohypophysis of the pituitary gland. THese veins break up into small capillaries and actually account for the control of the hormones released by the adenohypophysis

STH- Adenohypophysis

ACTH- Adenohypophysis

TSH- Adenohypophysis

FSH- Adenohypophysis

LH- Adenohypophysis

LTH- Adenohypophysis

_____ or thyrotropin exerts its effect upon the thyroid gland and stimulates the production of the thyroid hormones, thyroxine (T4), Liothyronine (T3) and calcitonin (thyrocalcitonin)

NAme the 3 thyroid hormones

Thyroid stimulating hormone (TSH) stimulates the synthesis of ____ by thyroid gland cells and stimulated the release of thyroid hormones.

The thyroid gland consists of follicles filled wiht material called ____, the majority of which consists of a protein-iodine complex called ____. _____ _______ are present in the thyroid gland in addition to the regular follicular cells.

The C cells produce _____ which lowers the blood level of calcium. ______ raises Ca blood level by absorbing Ca from the bone. Therefore these are _____

Thyroglobulin is the parent unit for:
1. Levothyroxine Sodium (tetraiodotyrosine)- T4 Brand Name:
2. Liothyronine sodium (triiodotyrosine)- T3 Brand Name:

3 internal diseases that cause bilateral alopecia

Thyroglobulin requires ___ as an essential part to form T3 and T4 and be biologically active.

Iodine in the blood is in the form of ____, but in the thyroid gland it is in the form of ____ or ____

The oxidized form combines with ____ (aa) in the synthesis to T3 and T4.

The thyroid gland traps iodide in the ____ and oxidizes it to ____. The Iodine is then incorporated into the amino acid ___, form ______ (MIT) and ______(DIT). Subsequent coupling of these iodotyrosine form ______(triiodotyrosine) and ____(tetraodotyrosine)

What is the Name for T3?

What is the name for T4?

___ is formed and stored in the thyroid gland and is the main secratory product of this thyroid gland.

Less than ____ of T3 is formed in the tyroid gland; the remaining T3 is formed from the _____ of T4

The primary functions of T3 and T4

Foods that are Goitrogenic (hyperthyroglobulin production)

4 clinical symptoms of Hypothyroidism

5 Metabolic symptoms of Hypothyroidism

4 clinical symptoms of Hyperthyroidism

4 Dermatological symptoms of Hypothyroidism

is the most common form, occurring in over 95% of cases , and is a result of destrcution of the thyroid gland

The most common symptoms of Primary Hypothyroidism can be summarized into two areas:

Because the Hypothyroidism develops so gradually, clinical signs are not noticeable until ___ of the thyroid has been destroyed.

Hypothyroidism starts at what age of dog?

Testing for Hypothyroidism; what two test are available.

Thyroid tumors in the cat produce excessive amounts of _____ and the cats develop the clinical syndrome hyperthyroidism. 6 signs are:

Some cats have ____________ a syndrome characterized by signs opposite to classic presentation for hyperthyroidism. eg depression, lethargy, and anorexia

Treatments for hyperthyroidism in cats include:

What is the most frequent diagnosed endocrine disorder in cats? Treatment of choice?

Hyperthyroidism in the Cat
Principle: _____ are the major secretory products of the thyroid gland and important hormones at target issues
Interpretation: _____ is the most reliable test to differentiate cats with hyperthyroidism from cats with non-thyroidal diseases.

________ is actively concentrated in the thyroid tissue and act there to block thyroid hormone sythesis at several steps. ____ uptake as well as the release of previosly synthesized and stored hormone are ____. some scientists believe uptake _____.

Secretion of adrenocoricotropic hormone (ACTH or adrenocortin) is regulated by ________ (CRH) from the _____.

ACTH regulates the production of glucocorticoids (____ and ______) and _________ as well as sex hormones from the  _____ of the adrenal gland. These are steroid-based hormones that affect cellular _____.

Name the 2 parts of the Adrenal Gland

Name the 4 parts of the Adrenal cortex- outer to inner

the outermost layer thought to be responsible for the secretion of mineralocorticoids

middle layer most responsible for secretion of the glucocorticoids although the reticularis does contribute

inner layer is the zone for sex steroids although total quantity is less than 5%

Name restricted to the hormones produced by the zona fasiculata of the adrenal cortex.

Corticosteroids are applied to:

Secreted in response to the production of gonadotropin releasing hormone (GnRH) from the hypothalamus

FSH acts on the _______ in the female animal to stimulate its development and maturation

In the male animal, FSH promotes the maturation of ___.

LH is another hormone regulated by ____. It stimulates _____ and development of the _____ in the female.

LH, In the male regulates production of the hormone ______ by the interstitial cells of Leydig in the testes.

In the male LH may sometimes be referred to as

The hormone Prolactin (PRL) 1. stimulates the development of the _______ of the pregnant female animal. 2. as well as playing as active role in ____ following parturition.

Name the 2 hypothalamic hormones that control prolactin's secretion

plays a critical role in all cellular growth. It regulates the production of proteins by cells and controls the energy used within the body.

During times of poor food supply it will stimulate the utilization of lipid as an energy source in order that essential glucose can be conserved from the nervous system. particularly important in young growing animals

GH production is regulated by what 2 hormones

The final hormone produced by the anterior pituitary is the former intermediate lobe hormone called

MSH is particularly important in the production of _____ in fish, amphibia, reptiles and many mammals although not in ____.

The secretion of MSH is regulated by melanocyte stimulating hormone inhibiting hormone (MSH-IH) produced by the

sometimes called the "third eye"; lies in the posterior part of the third ventricle of the brain.

_____ gland contains neurons, neuroglia, and specialized secretory cells called ____.

the pinealocytes secrete a hormone called ____ that forms the basis for the neurotransmitter molecule known as _____.

serotonin is secreted by ____

During periods of _____ production of melatonin is ___ while during _____ its production is __.

Melatonin is linked with the timing of ______, ___ and possibly with the maintenance of _____ rhythms.

Endocrine cells called _____ produce parathyroid hormone (PTH or Parathormone) in response to falling levels of calcium ions in the blood.

PTH stimulates the secretion of ____ by the kidney: this increases the efficiency with which calcium is absorbed from the digestive tract

PTH and Calcitonin are____

Hyperparathyroidism can occur in one of 3 ways.

can cause over production of PTH. This causes demineralization of bone and may cause the bones to weaken and fracture.

can be seen in cases of chronic renal failure, resulting in Ca loss. Body attempts to maintain level of Ca by absorbing more form the bone resulting in rubbery like bones _____

is not frequent today but can occur when dog is fed meat only. meat is low in Ca levels for dogs so the dog adjust with over-production of PTH

The thyroid gland lies just below the larynx and secretes three thyroid hormones:

T4&T3 regulate _______ via the mitochondria and the production of ATP

Calcitonin assists with regulation of _________ in the blood and is secreted when there is an ____ in the concentration of calcium ions above the threshold level.

Opposite in its effect to PTH, it causes a fall in the calcium ion concentration by inhibiting osteoclasts activity in bone and by promoting the secretion of calcium ions by the kidney in the urine.

is also thought to be improtant in the regulaton of bone growth in young animals and in maintainign the balance of calcium ions between bitch and fetus during pregnancy.

The thymus ("sweet bread") is located in the _____________

The thymus produces a hormone called _____ that promote __________ of lymphocytes. In this way it is thought to be a major contributing factor to the immune response in the young animal.

the walls of the atria contain endocrine cells that secrete a hormone, _________ when over stretched

_______ reduces blood volume

The kidney secrete two hormones

thought to have effects on muscle contraction, insulin release, and secretion of testosterone.

is released by the kidney when circulating blood oxygen levels are low. Its stimulates the bone marrow of long bones to increase the rate of production of rbc in an attempt to increase the oxygen carrying capacity of blood

The adrenal Cortex is divided into 3 layers

The outer layer of the adrenal gland called the cortex produces more than ___ different hormones all ____ based.

From zona glomerulosa and represented by ______ contributes to the regulation of electrolytes within the body, primarly sodium and potassium.

The zona fasciculata and zona reticularis, the ________ such as ____ and _____ are secreted at times of stress. They help to spare glucose by mobilizing other sources of energy such as amino acids and lipids.

______ a condition known as Cushing's disease.  The adrenal cortices produces excessive amount of glucocorticoids in particular ____.

6 symptoms of Cushings

85-90% of all cushings disease is due to ________ with the other 10-15% being from ____

is an adrenocorticlytic drug. Causes necrosis of the zona fasiculata and zona reticularis. hard to control but safer than Vetoyrl and more effective than Anipryl

as the animal ages, MAOB (monoamine oxidase-type B) production is increased and this results in a decrease of dopamine, which in turn results in hyperadrenocortism. this is given to the patient inhibinting the production of MAOB. Dopamine metabolism is restored and clin signs of cushings are minimized

this is an enzyme blocker of steroids synthesis acting specifically on the zona fasiculata to prevent the production of glucocorticoids or to prevent there release. Although this drug is the "latest and greatest" it is expensive , short lived in the system (not even 8 hrs) and is not as safe as op DDD

Anipryl is also used for ____ in humans

_________ is a condition known as Addisons disease. It occurs when the adrenal cortices cannot produce adequate levels of ______ resulting in the increase in the retention of ______.

_____ and ______ are also produced in the zona reticularis in small quantities by the adrenal cortex in bothe male and female animals. Some are converted into _____ though biochemical means

The adrenal medulla is stimulated by neurons from the ___________ to produce epinephrine and norepinephrine.

only 1% of pancreatic cells are endocrine in function and these are called _______

secrete a hormone called glucagon. This causes an increase in the blood glucose levels by stimulating the breakdown of glycogen in muscle and the liver.

secrete the well known insulin in response to a rise in blood glucose, for example, following a meal, Insulin promotes the uptake of glucose by cells and the conversion of glucose into glycogen by the liver and muscle tissue.

produce a hormone called somatostatin, which is secreted in response to peaks of insulin or glucagon production suppressing their release, thereby avoiding dramatic swings in the levels of blood glucose.

produce a hormone called pancreatic peptide. It is thought to affect the production of some of the pancreatic digestive enzymes and inhibit the contraction of the glall bladder.

is associated with the inability of an animal to produce adequate amounts of Antidiuretic Hormone (vasopressin), animals with this cannot control the amount of water secreted in the urine, and produce copious qunatities of dilute urine

the hormone called ____ produced by the testis and ovary, has a negative feedback upon the production of FSH from the anterior pituitary in both the male and female

Ovaries in the female produce two hormones depending upon what stage of ovulation

A third hormone is produced by the female during pregnancy in the corpus luteum placenta and uterus