Chapter 11- Endocrine system

Question 1

List the major endocrine glands

Answer 1

hypothalamus.
pituitary.
thyroid.
parathyroids.
adrenals.
pineal body.
the ovaries.
the testes.

Question 2

Peptide hormones

Answer 2

Consist of chains of a few to 200 or more amino acids arranged like pearls in a necklace
- they are hydrophilic

Question 3

Steroid hormones

Answer 3

Are lipids that are synthesized from cholesterol. They are hydrophobic

Question 4

Monoamine hormones

Answer 4

Catecholamines (epinephrine and noreprinephrine)

Question 5

Describe the structure and function of the pituitary gland

Answer 5

Called the master endocrine gland/Hypophysis

Two separate glands with different embryological origins, different structures, different functions

Anterior pituitary = adenohypophysis
* Produces hormones when stimulated
* Produces Stimulating hormones
–(“Trophic hormones” or Tropins”)
—–Prolactin
—- Thyroid stimulating hormones
—— Luteinizing
—- ACTH
—— Growth hormones

Posterior pituitary = neurohypophysis
* Stores and releases hormones

Question 6

Growth hormone

Answer 6

 Also known as somatotropin and somatotropic hormone
 Promotes body growth in young animals
 Helps regulate metabolism of proteins, carbohydrates, and lipids in animal’s cells
*Anabolism – proteins
* Catabolism – fats, carbohydrates

Anterior pituitary

Question 7

Adrenocorticotropic hormone

Answer 7

 Regulates response to STRESS!!!
 Stimulates adrenal cortex
 Regulated by feedback from hormones of adrenal
cortex
 ACTH can also be released quickly as a result of
stimulation of hypothalamus by other parts of brain

Anterior pituitary

Question 8

follicle stimulating hormone

Answer 8

Named for effect on females
 Effects in the female
*Stimulates oogenesis
*Stimulates production and secretion of estrogen
 Effects in the male
*Stimulates spermatogenesis

Anterior pituitary gland

Question 9

luteinizing hormone

Answer 9

Luteinizing Hormone (LH)
 Completes process of follicle development in ovary
 LH levels reach peak when follicle is fully mature
* Usually causes ovulation
* Causes development of corpus luteum
 LH in males stimulates interstitial cells to produce
testosterone

Anterior pituitary

Question 10

melanocyte stimulating hormone

Answer 10

Associated with control of color changes in pigment cells of reptiles, fish, and amphibians
* Rapid changes of colors and color patterns
 Administration of artificially large amounts to higher mammals
* Can cause darkening of skin by melanocyte stimulation

Question 11

oxytocin

Answer 11

Effect on uterus
* Induces uterine contractions at
breeding and parturition
 Effect on active mammary
glands
* Stimulation of teat by nursing or
milking causes oxytocin to be
released
* Causes movement of milk down
to lower parts of the mammary
gland (milk letdown)

Hypothalamus

Question 12

Thyroid gland

Answer 12

2 lobes on either side of larynx
Lobes may be connected by isthmus
2 hormones produced in follicles:
-Thyroid hormone
-Calcitonin

Question 13

Thyroid Stimulating hormone

Answer 13

Thyroid-Stimulating Hormone (TSH)
 Also known as thyrotropic hormone
 Stimulates growth and development of thyroid
gland
 Causes thyroid gland to produce its hormones
 Secretion regulated by:
* Feedback from thyroid
*Interaction among hypothalamus, anterior
pituitary, and thyroid glands

Question 14

calcitonin

Answer 14

 Produced by C cells located between thyroid
follicles
 Helps maintain blood calcium levels
 Prevents hypercalcemia by encouraging excess
calcium to be deposited in bones
 Parathyroid hormone is the other hormone involved
in maintaining blood calcium levels

Question 15

parathormone

Answer 15

A substance made by the parathyroid gland that helps the body store and use calcium

Question 16

list three categories of hormones produced by the adrenal cortex

Answer 16

glucocorticoid
mineralocorticoid
sex hormones

Question 17

list the hormones produced by the pancreatic islet cells

Answer 17

insulin, glucagon and somatostatin

Question 18

Insulin

Answer 18

Essential for life
causes glucose, amino acids and fatty acids in the blood stream to be absorbed through cell membranes

produced by the pancreas

Question 19

glucagon

Answer 19

Opposite effect of insulin
stimulates liver cells to convert glycogen to glucose
stimulates gluconeogenesis

Question 20

somatostatin

Answer 20

Somatostatin from the hypothalamus inhibits the pituitary gland’s secretion of growth hormone and thyroid stimulating hormone.

Question 21

Androgens

Answer 21

Male sex hormones
promote the development of male characteristics.

Question 22

estrogens

Answer 22

 Follicle cells produce and release estrogens
* FSH stimulates ovarian follicles to develop
* Follicle grows
*Amount of estrogen produced increases
*Anterior pituitary reduces FSH and increases LH
production
* LH peaks when follicle is fully mature
*Increasing estrogen levels accelerate physical and
behavioral change
* Ovulation occurs

Question 23

progestins

Answer 23

 Group of hormones produced by corpus luteum (ovary)
*Principal progestin = progesterone
 In pregnant female
* Corpus luteum produces progesterone, necessary for pregnancy to be maintained
 If no pregnancy occurs
* Lack of hormone causes corpus luteum to shrink and disappear

less important-
 Progestin-related drugs used therapeutically

Question 24

hormone produced by the kidneys

Answer 24

 Produce erythropoietin
*Stimulated by hypoxia
*Effect is to increase production of red blood cells
*Increased oxygen level slows down production
 Deficiency of erythropoietin
*Anemia often accompanies kidney disease or failure

Question 25

Erythropoietin

Answer 25

Hormone produced by kidney that stimulates red bone marrow to increase production of red blood cells

Question 26

Gastrin

Answer 26

Produced by the stomach stimulates production of gastric juices

Question 27

Secretin

Answer 27

Hormone produced by the small intestine Stimulates bicarbonate secretion

Question 28

cholecystokinin

Answer 28

Produced in small intestine stimulates pancreas to release digestive enzymes into the duodenum

Question 29

Placental hormones

Answer 29

*Estrogen *Progesterone * Chorionic gonadotropin (some species) * Relaxin (some species)

Question 30

Differences nervous system and endocrine gland

Answer 30

Nervous system * Uses chemicals to carry messages * Neurotransmitters produced by neurons * Travel short distances across synapses *Allows system to react quickly Endocrine system * Uses chemicals to carry messages * Hormones secreted directly into bloodstream * Travel long distances to reach targets *Body reacts more slowly to changes

Question 31

Hormones

Answer 31

Hormones are chemical messengers * Produced by endocrine gland or modified neurons *Travel via bloodstream *impact target organs  Produce effects only when they bind to their specific receptors in or on cells  Cell that has receptors for a particular hormone is a target of that hormone controlled by negative feedback system

Question 32

Endocrine physiology

Answer 32

Homeostasis!  Level of hormone in blood directly or indirectly “feeds back” to the gland that produced it  Activity of gland is affected * Negative feedback system *Activity decreased by rising levels of hormone *Positive feedback system *Activity increased by falling levels of hormone

Question 33

Negative Feedback system

Answer 33

When the level of a specific hormone drops below needed levels, the appropriate endocrine gland is stimulated to produce more hormone.  Once the proper hormone level is present in the bloodstream, stimulation of that endocrine gland is reduced and production of that hormone is reduced.

Question 34

Homeostasis examples

Answer 34

Body temperature  Heart rate  Blood pH  Levels of hormones  Blood pressure

Question 35

Is pancreas endocrine or exocrine

Answer 35

Both!!!!!

Question 36

Hypothalamus

Answer 36

Part of the diencephalon of the brain – nervous tissue  Links conscious mind with rest of body  Links cerebrum with endocrine system by regulating pituitary gland  Controls activities of the pituitary gland  Portal system of blood vessels links to anterior portion of pituitary gland  Modified neurons also secrete antidiuretic hormone (ADH) and oxytocin  Transported to posterior pituitary for storage  Released into bloodstream by nerve impulses from hypothalamus

Question 37

antidiuretic hormone

Answer 37

ADH Helps prevent diuresis  Released when hypothalamus receptors detect dehydration * More-concentrated urine is produced *ADH travels to the kidney – causes kidneys to reabsorb more water (WHERE?) from the urine and return it to the bloodstream  ADH deficiency causes diabetes insipidus *Polydipsia and polyuria hypothalamus

Question 38

Anterior Pituitary Hormones

Answer 38

 Growth hormone  Prolactin  Thyroid-stimulating hormone (TSH)  Adrenocorticotropic hormone (ACTH)  Follicle-stimulating hormone (FSH)  Luteinizing hormone (LH)  Melanocyte-stimulating hormone

Question 39

Prolactin

Answer 39

Helps trigger and maintain lactation  Production and release continues as long as teat continues to be stimulated by nursing or milking  Without stimulation from prolactin: * Milk production stops * Mammary gland shrinks back to non-lactating size  No known effect in male mammals Anterior pituitary

Question 40

Thyroid hormones

Answer 40

T4 = tetra-iodothyronine = thyroxine *A prohormone, a circulating reservoir  T3 = tri-iodothyronine * The active hormone  Hormones are produced when TSH from anterior pituitary stimulates the thyroid gland Effect every cell in the body

Question 41

Effects of thyroid hormones

Answer 41

 Regulates metabolic rate of all body’s cells * Calorigenic effect *Allows animals to maintain constant internal body temperature  Affects metabolism of proteins, carbohydrates, and lipids *Anabolism or synthesis of proteins, depending on animal’s diet * Maintains homeostasis of blood glucose level *Encourages catabolism of lipids

Question 42

Parathyroid

Answer 42

4 small glands posterior to thyroid gland  Parathyroid hormone (parathormone) * Opposite effect ofcalcitonin *Prevents hypocalcemia

Question 43

Parathyroid hormone

Answer 43

Also called parathormone  Produced by the parathyroid glands *Small, pale nodules in, on, or near the thyroid glands  Helps maintain blood calcium levels  Prevents hypocalcemia * Causes kidneys to retain calcium and intestine to absorb calcium from food; withdraws calcium from bones *Exerts the opposite effect of calcitonin

Question 44

Adrenal glands

Answer 44

 Located near cranial ends of kidneys  Consist of two glands: *Adrenal cortex *Adrenal medulla

Question 45

Adrenal cortex

Answer 45

The Adrenal Cortex Produces numerous hormones:  Glucocorticoids (cortisone, cortisol, corticosterone) * Cause general hyperglycemic effect * Help maintain blood pressure * Help body resist effects of stress  Mineralocorticoids (e.g. aldosterone) * Regulate levels of electrolytes  Sex hormones (androgens, estrogens

Question 46

Glucocorticoids

Answer 46

Cortisone, cortisol  Gluconeogenesis * Hyperglycemic effect  Helps maintain blood pressure  Helps animal’s body resist effects of stress Produced in the adrenal cortex

Question 47

Mineralocorticoids

Answer 47

Aldosterone * Works with ADH  Electrolyte homeostasis * Regulate levels of important electrolytes (mineral salts) in animal’s body  Targets kidneys to  Na+ retention, reduce urine volume Adrenal gland

Question 48

Adrenal Medulla

Answer 48

Resembles nervous tissue  2 hormones produced *Epinephrine and norepinephrine *Secretion controlled by sympathetic portion of autonomic nervous system functions * “Fight or flight" response  Increases heart rate and output, increases blood pressure, dilates air passageways in lungs, and decreases GI function

Question 49

Pancreas

Answer 49

Long, flat organ located in theabdomen near the duodenum. Has both exocrine and endocrine functions  Only gland in body with exocrine and endocrine function  Exocrine – digestive enzymes  Endocrine – small % of pancreas * Hormones regulating glucose *Islets of Langherhans *Pancreatic islets, or islets of Langerhans *Alpha cells – produce glucagon *Beta cells – produce insulin * Delta cells – produce somatostatin

Question 50

Pancreatic hormones

Answer 50

Insulin  Lowers blood glucose levels * Causes glucose, amino acids, and fatty acids in blood to be absorbed into body cells Glucagon  Raises blood glucose levels *Stimulates liver cells to convert glycogen toglucose *Stimulates glycogenesis (gluconeogenesis)

Question 51

Testes

Answer 51

2 testes housed in scrotum  Seminiferous tubules *Spermatogenesis  Interstitial cells * Clumps of endocrine cells * Produce androgens when stimulated by LH  Testosterone * Primary androgen * Provides for development of male secondary sex characteristics and accessory sex glands * Activates spermatogenesis

Question 52

Testosterone

Answer 52

Androgens *Anabolic effect Made in the testes

Question 53

Ovaries

Answer 53

Produce ova and hormones in cycles  Cycles controlled by FSH and LH  Hormone groups produced: *Estrogens --From ovarian follicles *Estradiol and estrone *Progestins -- From corpus luteum --Equine – used to synchronize estrous periods in mares * Relaxin

Question 54

Relaxin

Answer 54

Effects of hormone * Relaxation of ligaments surrounding birth canal * Mammary development

Question 55

Cholesterol is the building block for what hormones

Answer 55

Progesterone, estrogen, cortisol, testosterone, aldosterone

Question 56

Stomach's hormone production

Answer 56

 Gastrin: produced by cells in the wall of the stomach  Secretion stimulated by presence of food in the stomach  Stimulates gastric glands to secrete hydrochloric acid and digestive enzymes  Encourages muscular contractions of the stomach wall

Question 57

Small intestine hormone production

Answer 57

 Secretin and cholecystokinin produced by cells in lining of small intestine in response to presence of chyme in duodenum  Secretion occurs in response to presence of chyme in duodenum  Secretin stimulates pancreas to secrete fluid to neutralize acidic chyme after it passes out of the stomach  Cholecystokinin stimulates pancreas to release digestive enzymes into the duodenum

Question 58

Thymus hormone production

Answer 58

 Extends cranially from the level of the heart up into neck region along both sides of the trachea  Large in young animals, atrophies later in life  Function involves hormones or hormone-like chemical substances (e.g., thymosin and thymopoietin)  Seems to cause certain cells to be transformed into T-lymphocytes

Question 59

Pineal Body hormone

Answer 59

 A part of the brain  Influences the body’s biological clock  Produces the hormone melatonin *Affects moods and wake-sleep cycles *“Jet Lag”?  * May also have role in timing of seasonal estrus cycles

Question 60

Prostaglandins

Answer 60

 Hormone-like substances (“tissue hormones”) derived from unsaturated fatty acids  Produced in a variety of body tissues (skin, intestine, brain, kidney, lungs, reproductive organs, and eyes)  Influence blood pressure, blood clotting, inflammation, GI, respiratory, reproductive, and kidney function  Non-steroidal anti-inflammatory drugs (NSAIDS) * Inhibit synthesis of certain prostaglandins * Side effects (Rimadyl, Deramaxx, Metacam)