Catos Endocrine System

Front 1

Broadly speaking, what is the role of the hypothalamus in the endocrine system?

Back 1

It coordinates communication between the nervous and the endocrine systems, by regulating the behavior of most glands.

Front 2

What are the six signaling methods of the nervous and endocrine systems?

Back 2

Gap Junctions, Autocrine, Endocrine, Paracrine, Neurotransmission, and Neuroendocrine

Front 3

How is neuroendocrine signaling different from the classic neurotransmission we've studied thus far?

Back 3

Instead of synapsing on another cell (i.e. axon to dendrite), the neurotransmitter is released directly into the vasculature, where it travels.

Front 4

Generally, the 10 characteristics of endocrine glands.

Back 4

1. Ductless glands
2. Vascularized
3. Anatomical distribution (3)
4. Simplicity
5. Parenchymal distribution (4)
6. The product is ALWAYS called a hormone.
7. Have a distinct target
8. Are controlled via feedback
9. Their individual chemistry and permeability is categorizable.
10. Disease either makes them hypo or hyper active.

Front 5

The two endocrine capillary types and location examples.

Back 5

1. Sinusoidal: The primary and secondary capillary beds in the adenohypophysis.
2. Fenestrated: The capillary bed of the neurohypophysis.

Front 6

The 3 anatomical distributions of endocrine glands

Back 6

1. Special all-endocrine cell glands (adrenal)
2. Mixed endo and exo cell glands (pancreas)
3. Endocrine cells in weird spots all alone (DNES)

Front 7

The fibrous capsule of endocrine glands is made of...

Back 7

Type I dense irregular collagen

Front 8

What would the parenchyma of an endocrine gland be made of?

Back 8

Well if the stroma is collagen, the parenchymae are the endocrine cells themselves.

Front 9

Describe the 4 parenchymal arrangements of the endocrine gland

Back 9

1. Unicellular (DNES)
2. Cords (parathyroid)
3. Follicular (thyroid)
4. Multipolar neurons (how the hypothalamus communicates with the pituitary, for example)

Front 10

What gland product is not stored, and why? How does a cell avoid releasing this product all the time?

Back 10

Steroids. Being lipid soluble, they immediately diffuse through the PM. Steroid hormones are stored as their precursor, cholesterol.

Front 11

What are the two ways hormone secretion can be regulated at the level of proteins?

Back 11

1. Hormones can be made as inactive prohormones.
2. Inactive hormones can be "activated" by biochemical interactions in the blood.

Front 12

How does a hormone act on its target?

Back 12

Same way as everybody else. It needs a receptor.

Front 13

The three types of closed negative feedback loops

Back 13

1. Autocrine (Ultrashort)
2. Short (Cell B's product inhibit's Cell A)
3. Long (Cell C's products affects both B and A)

Front 14

Examples of the mostly rare positive feedback loops in the body

Back 14

Blood clotting, birth contractions, immunoresponse

Front 15

List the major tyrosine derivatives and their locations

Back 15

1. Epi/Norepi (Adrenal)
2. T3/T4 (Thyroid)
3. Melatonin/Seratonin (Pineal)

Front 16

Name the major small peptide hormones and their origins

Back 16

1. ADH and Oxytocin (Neurohypophysis)
2. ANP (Atrium)

Front 17

Name the pancreatic protein hormones

Back 17

Glucagon, Insulin, Somatostatin, Pancreatic Polypeptide

Front 18

The hormones made by the Adenohypophysis are all...

Back 18

Proteins.

Front 19

The protein hormone of the parathyroid gland

Back 19

PTH

Front 20

Name the major steriod hormones and their origins

Back 20

1. Aldosterone, Cortisol (Adrenal Cortex)
2. Estrogen, Progesterone (Ovaries)
3. Testosterone (Testes)

Front 21

Name the origin of the Eicosinoids

Back 21

Every cell except RBCs

Front 22

The gas hormone and its origin

Back 22

Nitric Oxide, endothelium

Front 23

The two hydrophobic classes of hormone

Back 23

Steroid and thyroid.

Front 24

Flow of protein hormone interaction

Back 24

1. PM surface receptor
2. The surface receptor activates a kinase
3. The kinase phosphorylates regulatory proteins
4. Metabolic response is elicited.

Front 25

Flow of lipid-soluble hormone interaction

Back 25

1. Cross PM to interact with cytosolic/nuclear proteins
2. The hormone-receptor complex translocates to nucleus
3. Binds to DNA as a complex to stimulate transcription.

Front 26

Are there always hormones in blood?

Back 26

Yes, most of them are bound to a plasma protein until needed.

Front 27

What is upregulation?

Back 27

An increase in hormone concentration or an increase in hormone receptors

Front 28

Define the permissive effect

Back 28

A second hormone must be present for the first hormone to work at highest efficiency

Front 29

What can the permissive effect do?

Back 29

Increase the number of receptors for a given hormone or synthesize a necessary protein for that hormone's signaling cascade.

Front 30

Define the synergistic effect

Back 30

Two hormones working together greatly enhance their effects. Typically they can't work alone.

Front 31

Is the pituitary gland directly connected to the hypothalamus?

Back 31

You bet.

Front 32

The embryological origin of the neurohypophysis

Back 32

Neural ectoderm

Front 33

The two parts of the neurohypophysis

Back 33

The infundibulum (consisting of stalk and medial eminence) and the pars nervosa

Front 34

The embryological origin of the adenohypophysis

Back 34

Oral cavity epithelial ectoderm

Front 35

The three parts of the adenyhypophysis

Back 35

The pars tuberalis, pars intermedia, pars distalis

Front 36

Where is the pituitary gland? What covers it? What is above the covering?

Back 36

The sella turcica (Turkish saddle). The diaphrama sellae (dura mater). The infundibular stem and the pars tuberalis together form the pituitary stalk.

Front 37

What is the arrangement of the parenchyma of the pars distalis?

Back 37

Cords

Front 38

Two major parenchyma cell types of the pars distalis. How is this distinction made?

Back 38

Chromophobes/Chromaphils. The cytoplasm of "phils" takes a stain, while that of the "phobes" does not.

Front 39

Which parenchymal cell is the secretory cell of the pars distalis? What are the two types?

Back 39

The chromophils. Acidophils and basophils.

Front 40

What are the two products of acidophils? What are their trophic destinations?

Back 40

Growth hormone (somatotroph), prolactin (mammotroph).

Front 41

What are the 4 products of basophils? What are their trophic destinations?

Back 41

TSH (thyrotroph)
FSH (gonadotroph)
LH (gonadotroph)
ACTH (corticotroph)

Front 42

Why are there two types of follicle-stimulating hormone? Two types of luteinizing hormone?

Back 42

One set for each gender. The gonadal tissue they stimulate is different.

Front 43

Flow of blood into adenohypophysis

Back 43

Superior hypophyseal artery--> primary sinusoidal capillary in medial eminence--> portal vein--> secondary sinusoidal capillary bed in pars distalis.

Front 44

What is the point of the hypothalamus-hypophyseal portal system?

Back 44

Hormones released into blood via hypothalamus go DIRECTLY to the pituitary, bypassing normal circulation.

Front 45

What is the signaling mechanism of the hypothalamus?

Back 45

Neuroendocrine.

Front 46

Name the 4 releasing hormones of the hypothalamus and the cells they stimulate in the pituitary.

Back 46

1. GnRH (gonadotrophs=FSH, LH)
2. CRH (corticotrophs=ACTH)
3. TRH (thyrotrophs=TSH)
4. GHRH (somatotrophs=hGH)

Front 47

Name the two inhibitory hormones of the hypothalamus and the cells they stimulate in the pituitary

Back 47

1. Somatostatin (stops somatotrophs)
2. Dopamine (stops mammotrophs)

Front 48

Is the pars intermedia really important?

Back 48

No, it usually atrophies in adults.

Front 49

The three hypothalamic neurons that stimulate ONLY the adenophysis?

Back 49

Arcuate, dorsomedial, ventromedial.

Front 50

Why is the neurohypophysis called that?

Back 50

It is comprised of neural axons that grew down from the hypothalamus, specifically the paraventricular and the supraoptic nuclei.

Front 51

What are Herring bodies?

Back 51

Secretory granules of neurons in the pars nervosa

Front 52

What are the two secretory products of the pars nervosa? What are their hypothalamic origins?

Back 52

Oxytocin (neurons from the paraventricular nucleus) and ADH (neurons from the supraoptic nucleus)

Front 53

A Herring body containing Oxytocin...

Back 53

...will also contain ATP and neurophysin 1

Front 54

A Herring body containing ADH

Back 54

...will also contain ATP and neurophysin 2

Front 55

Since the neurohypophysis is made up of specialized neurons, what else would you expect to find there?

Back 55

Supportive neuroglia! In this instance, the astrocytes are called pituicytes.

Front 56

Purpose of oxytocin

Back 56

Lactate and contract to give birth.

Front 57

What is the MAIN signaling difference between the adenohypophysis and the neurohypophysis?

Back 57

The cells of the pars distalis receiving their signal from hypothalamic neurons to release hormones, while the cells of the pars nervosa ARE THE HYPOTHALAMIC NEURONS. So one is classic neurotransmission, and the other is neuroendocrine.

Front 58

Purpose of ADH

Back 58

Stimulate the kidneys to resorb as much water as possible.

Front 59

What is the DNES?

Back 59

Scattered unicellular polypeptide secretory cells that mostly make/store bioactive amines. They are all over the place, hence the name diffuse neuroendocrine system.

Front 60

The 3 major hormone products of the enteroendocrine system?

Back 60

1. Gastrin -- secretion, mobility, growth of mucosae
2. Secretin -- bile and pancreatic juice.
3. Cholecystokin -- everything secretin does and makes you feel full.

Front 61

What does vasoactive intestinal peptide do?

Back 61

Inhibits gastric acid secretion.

Front 62

What cells make up the follicles of the thyroid gland? What is inside a follicle?

Back 62

Follicular and parafollicular cells. The inside contains colloid, mostly made of thyroglobulin.

Front 63

Define the cellular orientation of a follicular thyroid cell.

Back 63

The apical membrance faces the inside of the sphere, into the colloid. The basal membrane is synonymous with the external lamina of the follicle.

Front 64

How is the thyroid stimulated?

Back 64

Nervous: Sympathetic
Hormonal: TSH from the pituitary

Front 65

What increases the level of TSH?

Back 65

Low temp, puberty, pregnancy

Front 66

What decreases the level of TSH?

Back 66

Emotional stress, systemic stress

Front 67

Flow of thyroid hormone production

Back 67

1. Thyroglobulin is made from tyrosine and released into colloid.
2. Follicular cells take up iodine and oxidize it (peroxidase)
3. Apical enzymes attach iodine to thyroglobulin.
4. Everybody hangs out in the colloid until TSH hits the basal membrane of the follicular cells.
5. Io+Thyroglob is endocytosed, converted to T3 or T4 in lysosomes.
6. T3 and T4 are kicked back out the basal membrane into the vasculature.

Front 68

What do T3 and T4 do?

Back 68

Increase metabolism and energy-requiring cell functions.

Front 69

From the hypothalamus on down, how is the thyroid stimulated?

Back 69

Hypothalamus makes TRH -> TRH stimulates thyrotrophs in pars distalis to make TSH -> TSH interacts with receptors on basal membrane of follicular cells in thyroid.

Front 70

How is the thyroid stimulating pathway shut off?

Back 70

Negative feedback from T3 and T4 stop both the hypothalamus from making TRH and the pituitary from making TSH

Front 71

Percentages of T3 and T4 in the bloodstream

Back 71

90% T4, 10%T3

Front 72

What kind of capillary feeds the follicular and parafollicular cells of the thyroid?

Back 72

Fenestrated.

Front 73

What where and why on parafollicular cells?

Back 73

DNES cells located between follicular cells and the basement membrane. They secret calcitonin when Ca++ levels are too high in blood. The osteoclasts busy resorbing bone are shut off.

Front 74

The embryological origin of the thyroid and parathyroid glands?

Back 74

Endoderm.

Front 75

Can you live without the parathyroid?

Back 75

No.

Front 76

What kind of capillary feeds the parathyroid gland?

Back 76

Fenestrated.

Front 77

What are the two types of parathyroid cells?

Back 77

Chief, Oxyphil

Front 78

Does the hypothalamus regulate the parathyroid gland?

Back 78

No. The parathyroid is regulated by levels of Ca++ and phosphate.

Front 79

What do chief cells do? What does their secretory product do?

Back 79

Make PTH. PTH increases blood calcium by stimulating bone resorption, increasing phosphate excretion in kidneys while taking up more calcium, and increasing uptake of Ca++ in intestine.

Front 80

What do oxyphils do?

Back 80

Apparently nothing.

Front 81

The two functional parts of the adrenal gland?

Back 81

The outer cortex and inner medula.

Front 82

How do you know something was made by the adrenal gland?

Back 82

It has the latin prefix "cortico" somewhere in the name.

Front 83

The embryological origin of the adrenal gland.

Back 83

Cortex: mesodermal
Medulla: neural crest ectoderm.

Front 84

Can you live without an adrenal cortex?

Back 84

No. You can live without the medulla.

Front 85

What are all steroid hormones made from?

Back 85

Cholesterol.

Front 86

What are the three steroid products of the adrenal cortext=?

Back 86

Mineralcorticoids, glucocorticoids, androgens.

Front 87

Stick a pin into the adrenal medulla and list the layers you'll hit in order?

Back 87

Capsule, zona glomerulosa, zona fasciculata, zona reticularis, medulla

Front 88

What is a mineralocorticoid and what does it do?

Back 88

The product of the zona glomerulosa, i.e. aldosterone, regulates renal function.

Front 89

Flow chart of mineralocorticoid activation

Back 89

Severe dehydration prompts the kidneys to release renin -> renin cleaves angiotensinogen to angiotensin I -> angiotensin I is activated by ACE to angiotensin II -> a II tells zona glomerulosa to release aldosterone -> Aldosterone stimulates the uptake of Na back into the blood, and water follows happily along.

Front 90

Type of capillary in the zona fasciculata

Back 90

Sinusoidal.

Front 91

What hormone does the zona reticularis make?

Back 91

Androgens, or masculinizing hormones.

Front 92

What hormone do the zona fasciculata and the zona reticularis make together?

Back 92

All the glucocortoids and the gonadocortoids. I.E. cortisol

Front 93

Flow of glucocortoid synthesis

Back 93

Hypothalamus releases CRH -> CRH stimulates corticotrophs in pars distalis to make ACTH -> ACTH stimulates z. fascic. and z. retic. to make glucocortoids. GLUCOCORTOIDS raise blood sugar.

Front 94

Other than stimulating mineralcorticoid production, what does angiotensin II do?

Back 94

SERIOUS ARTERIOLE VASOCONSTRICTION.

Front 95

The two cells types of the adrenal medulla

Back 95

Chromaffin cells and ganglion cells.

Front 96

What is a chromaffin cell really?

Back 96

A postgang sym neuron that lost it's neural characteristics over evolutionary time.

Front 97

What do chromaffin cells do?

Back 97

Make norepi and epi.

Front 98

What two types of blood supply feed the adrenal medulla? Why is this critical? KNOW THIS

Back 98

Sinusoidal capillaries and cortical arterioles.
1. The transferase that makes epi from norepi requires stimulation from steroids made in the cortex.
2. An arteriole can't carry the steroids, so the cells around the arteriole will make only norepi. 15%
3. The sinusoidal capillaries CAN carry the steroids, so the cells around them will make epi. 85%

Front 99

REVIEW: What do epi and norepi do?

Back 99

Epi: increase blood glucose, alertness, heart rate.
Norepi: increase blood pressure.

Front 100

So the hypothalamus makes CRF, the pituitary releases ACTH, and ACTH tells the adrenal cortex to make steroid hormones. Once there are enough hormones, the hypothalamus and pituitary shut off. It's normal, so what and when is this pathological?

Back 100

Well the steroids basically "up-regulate" the energy use of the body in stressful situations. Under constant stress, the body will begin to eat itself because the pathway never shuts off. The body is constantly requiring energy and never resting.
The second problem is having all those steroids around all the time. They are immunosuppressant, so a chronically stressed person is extremely likely to get ill.

Front 101

What is the purpose of the large fetal adrenal cortex?

Back 101

Synthesis of estrogen precursors for export to the placenta for activation. The placenta cannot make estrogen directly itself.

Front 102

Embryological origin of the Islets of Langerhans

Back 102

Endoderm. DNES.

Front 103

4 types of pancreatic islet parenchyma, and what they do.

Back 103

alpha: make glucagon
beta: make insulin
F: make pancreatic polypeptide, inhibit exocrine secretion
delta: produce somatostatin. INHIBITS EVERYBODY ELSE.

Front 104

What is the cause of diabetes mellitus?

Back 104

B cell malfunction, or insulin insufficiency.

Front 105

What feedback regulator affects alpha and beta cells of the pancreatic islets?

Back 105

blood glucose levels.

Front 106

What are corpora arenacea?

Back 106

Calcium and phosphate deposits in the interstitium of the pineal gland.

Front 107

What are the cells of the pineal parenchyma?

Back 107

Pinealocytes: tortuous extensions to drop secretory product into blood vessels.
Glial: As usual, support.

Front 108

What's special about the pineal gland?

Back 108

During the day, it produces seratonin. At night, it produces melatonin.

Front 109

You open your eyes and see darkness. What happens in the pineal gland?

Back 109

A signal travels from the retina to the hypothalamic suprachiasmatic cells to the pregang syms of T1-4 to the postgang neurons in superior cervical ganglia and voila! The enzymes begin to make melatonin from seratonin.

Front 110

What is hydroxyindole-O-methyl transferase?

Back 110

Makes melatonin from seratonin.

Front 111

Where does melatonin go once synthesized?

Back 111

To the hypothalamus, to propogate a hormonal cascade.

Front 112

What does melatonin do?

Back 112

Potentially eliminate free radicals, temperature regulation,

Front 113

Endorphins are made from the same parent compound as what?

Back 113

ACTH

Front 114

What hormone counteracts both ADH and aldosterone?

Back 114

ANP

Front 115

Where on thyroglobulin does iodine bind?

Back 115

Tyrosine residues.

Front 116

**What causes diabetes insipidus?

Back 116

hyposecretion of ADH

Front 117

What group of hormones is derived from arachidonic acid? What group is derived from cholesterol?

Back 117

Eiconsanoids. Steroids.

Front 118

Somatotrophs of the pars distalis secrete what?

Back 118

GH

Front 119

What stimulates the parathyroid to release PTH?

Back 119

Low blood calcium

Front 120

Too much GH? Too little?

Back 120

Giantism. Pituitary dwarfism

Front 121

Too much TSH? Too little?

Back 121

Hyperthyroidism. Hypothyroidism.

Front 122

Too much ACTH? Too little?

Back 122

Hyper vs. hypoadrenalism.

Front 123

Too much T3/T4? Too little?

Back 123

Grave's disease. Cretinism.

Front 124

Too much PTH? Too little?

Back 124

Osteitis fibrosa. Hypocalcemia.

Front 125

Too much mineralcorticoid? Too little?

Back 125

Cushing's disease. Addison's disease.

Front 126

Too little glucocorticoids?

Back 126

Addison's disease.

Front 127

Too much epi/norepi?

Back 127

Pheochromocytoma.

Front 128

Too much melatonin? Too little?

Back 128

Delayed sexual development. Precocious sexual development.