Chapter 13 - Endocrine Flashcards
What are the 4 types of communication mechanisms between cells?
gap junctions, neurotransmitters, paracrines and hormones
What type of glands have ducts?
exocrine
What type of glands secrete onto the mucus membrane of the digestive tract?
exocrine
What type of glands have fenestrated capillary networks?
endocrine
Give examples of 2 organs that defy the rigid classifications
liver - hormones, bile into ducts and non hormones such as albumin. sex organs also!
What system has a more widespread affect? Nervous vs. endocrine
Endocrine
Name 3 chemicals that function as both hormones and neurotransmitters
norepinephrine, dopamine and ADH
What structure forms the floor and walls of the third ventricle of the brain?
hypothalamus
The pituitary gland is found where?
sella turcica of the sphenoid bone
The pituitary gland is suspended from a stalk called the ______.
Infundibulum
Name the anterior and posterior parts of the pituitary gland.
adenohypophysis
Neurohypophysis
What lobe of pituitary is bigger?
anterior
Primary capillaries are located in the hypothalamus or the pituitary?
hypothalamus
How many hormones does hypothalamus release/synthesize?
8
How do hormones from the hypothalamus get to the anterior pituitary?
hypophyseal portal system
What kind of tissue makes up the neurohypophysis?
nerve tissue
How do hormones get from the hypothalamus to the posterior pituitary?
hypothalamo-hypophyseal tract
How many hormones regulate the anterior pituitary?
6
How many hormones regulate the posterior pituitary/stored there?
2
Name the 6 releasing and inhibiting hormones released by the hypothalamus to stimulate the anterior pituitary gland
TRH GnRH CRH GHRH PIH Somatostatin
What are the 2 inhibiting hormones from the hypothalamus?
somatostatin (GHIH) and PIH (dopamine)
What 2 hormones are synthesized by the hypothalamus and then stored in the posterior pituitary?
OT, ADH (vasopressin)
What does TRH do?
promotes TSH and PRL
What does CRH do?
ACTH
What does GnRH do?
FSH and LH
What does GHRH do?
GH
What does PIH do?
Inhibits PRL release
What does somatostatin do? (from hypothalamus)
inhibits GH and TSH
Name the hormones secreted by the anterior pituitary gland:
TSH, PRL, GH, ACTH, FSH, LH
Stimulation of the PVN leads to what hormone being released from the posterior pituitary?
OT
Stimulation of the SON leads to what hormone being released from the posterior pituitary?
ADH (vasopressin)
What does ADH do to urine volume and water retention?
Decrease urine volume and increases water retention!
Name the 3 effects of GH?
- Increased protein synthesis
- Increased fat catabolism
- sparing glucose for brain and releasing more glucose from the liver
What gland is attached to the roof of the 3rd ventricle?
pineal gland
What gland may influence the timing of puberty?
Pineal gland
Where is the thymus located?
mediastinum superior to the heart
What is the thymus a site of?
T-cell maturation
What is the largest gland that is purely endocrine?
thyroid
What color is the thyroid?
darkish brown
Thyroid is made up of:
follicles
Follicle cells are filled with:
colloid
Follicles are lined by what type of cells?
follicular cells- simple cuboidal
What cells are in the thyroid besides the follicular cells?
The parafollicular cells
The parafollicular cells secrete what substance?
calcitonin
What effect does calcitonin have?
reduces blood calcium, stimulates osteoblasts
How many parathyroid glands are there usually?
4
What does PTH do? Name 4 effects for full points!!!!
- Promotes synthesis of calcitriol
- Increases absorption of calcium
- Decreases urinary excretion of calcium
- Increases bone resportion
What glands sit on top of kidneys?
Adrenal glands
Describe how adrenal cortex and medulla are developed
from different origins and functions - merged
The inner core of the adrenals is the:
medulla
The inner core of the adrenals makes up what percent of the overall adrenal?
10-20%
The adrenal medulla acts as both a _______ and ______>
endocrine gland
ganglion of sympathetic nervous system
The medulla consists of cells that are called:
chromaffin cells
What are chromaffin cells?
sympathetic postganglionic neurons that secrete catecholamines!
What are the 3 catecholamines?
epinephrine, norepinephrine and dopamine
Catecholamines have what effects on the body?
boost alertness, prepare fuel so thus boost glucose levels, epinephrine inhibits insulin and thus spares glucose, increased blood pressure, decreases digestion and urine production
What are the 3 layers of the adrenal cortex?
- zona glomerulosa - secretes mineralcorticoids such as aldosterone
- Zona fasciculata - secretes glucocorticoids such as cortisol
- Zona reticularis - secretes sex steroids
What layer of the adrenal cortex is the thickest?
zona fasciculata - the middle layer
Pancreas contains what type of cells?
islets
What do the alpha cells of the pancreas secrete and what effect does this hormone have?
glucagon, increases blood glucose and fat catabolism
What do beta cells secrete and what effect does this substance have?
insulin, reduces blood glucose, leads to synthesis of glycogen, fat and protein
What 4 organs/cells absorb glucose without insulin?
liver, kidney, RBC, brain
What do Delta cells secrete and what does this hormone do?
somatostatin, inhibits glucagon and insulin
Name 6 hormones that increase blood glucose:
glucagon, epinephrine, norepinephrine, cortisone, cortisol, GH
What are the exocrine product of ovaries and testes?
egg and sperm
What are the endocrine product of ovaries and testes?
sex hormones
Name the 3 ovarian hormones:
estradiol, progesterone, inhibin
Name 3 testicular hormones:
testosterone, estrogen, inhibin
Describe an follicle in the ovary:
egg surrounded by GRANULOSA cells and a capsule called a theca
The theca cells synthesize _______ which is converted to mainly ______ by granulosa cells.
androstendione, estradiol
After ovulation the remains of the follicle becomes:
corpus luteum
What does the corpus luteum secrete?
progesterone and inhibin
What does inhibin do?
suppresses FSH secretion from ant. pit.
What structure(s) produce sperm in the testes?
seminiferous tubules
Tubule walls of seminiferous tubules contain what kind of cells?
sertoli cells - single cells
In between the seminiferous tubules are the ______ cells
leydig cells - clusters
Leydig cells do what?
produce hormones such as testosterone
Sertoli cells do what?
help sperm develop and secrete inhibin
Again what does inhibin do?
limits FSH secretion!
In the skin keratinocytes convert cholesterol-like steroid into:
cholecalciferol using UV from the sun
How does liver play into the production of vitamin D?
Converts cholecalciferol into calcidiol
What hormones/substances does the liver secrete?
- angiotensinogen (precursor of angio” 1)
- 15% of EPO
What are the hormones/substances that the kidneys play a role in?
- calcitriol (Active form of vit. D
- renin, which converts angiotensinogen to angiotensin 1
- 85% of EPO (Stimulates red blood cells!)
How is angiotensin II created?
enzymes in the lungs
What hormone(s) does the heart secrete and what does it do?
ANP - atrial natriuretic peptide in response to high blood pressure! decreased blood volume and blood pressure by increases water and electrolyte output
How many hormones do stomach and small intestines secrete about?
10
The placenta secretes what?
estrogen, progesterone, inhibin
What are the classes of hormones?
steroids, monoamines and peptides
What are steroids derived from?
cholesterol
Name the steroid hormones:
sex hormones and corticosteroids like cortisol
What are monoamines made from?
amino acids
Name the monoamine hormones:
catecholamines, melatonin and thyroid hormone
What are peptides and glycoproteins made from
chains of amino acids
Name peptide/glycoprotein hormones:
pituitary, hypothalamus, insulin and glucagon
How many carbon rings do steroids have?
4
How do steroids differ from one another?
functional groups attached to the 4 carbon backbone
Most monoamines and peptides are:
hydrophilic - like water
Name hydrophobic hormones:
steroids and TH
How do steroids cross the membrane?
with transport proteins such as albumins and globulins
Do bound hormones have a shorter or longer half-life than unbound hormones?
longer - transport proteins protect from breakdown
Where can hormone receptors be found in regards to a cell?
membrane and in the nucleus
How do peptide hormones interact with cells?
bind to surface receptor - g-protein coupled and second messengers
How do steroid hormone interact with cells?
penetrate plasma membrane and bind to internal receptors in the nucleus where they influence gene expression
Do steroids act quick or slow?
slow due to delay for protein synthesis
Describe steps of g-protein coupled receptor signaling
- Hormone bind to cell
- G protein activated
- Adenylate cyclase activated
- cAMP produced
- cAMP activates protein kinases
- Kinases phosphorylate enzymes and then downstream effects
What enzyme breaks down cAMP?
phosphodiesterase
Name an example of a synergistic effect:
FSH and testosterone on sperm production
Name an example of permissive effect:
estrogen prepares uterus for progesterone
Name antagonistic effect:
insulin vs. glucagon
Most hormones are degraded by what organs?
kidney and liver
Rate of hormone removal from blood is called:
metabolic clearance rate
The faster the MCR the ______ the half-life.
shorter!
Diabetes insipidus involves what?
less ADH, leading to more urination and electrolyte imbalances
Pheochromocytoma
tumor of the adrenal medulla
toxic goiter
too much TH secretion from antibodies
Endemic goiter is causes by what?
iodine deficiency
What causes hypoparathyroidism?
thyroidectomy complication, can involve tetany from too low of calcium
Hyperparathyroidism is causes by what and what does it involve?
too high calcium, tumor
Too much cortisol leads to?
cushings syndrome
AGS - adrenogenital syndrome involves what?
enlargement of external sex organs and masculinizing effects on women
