(04) Endocrine System - Pituitary Gland

Question 1

1. The endocrine system works with the nervous system to help maintain what?
2. The electrical signals generated by the nervous system brings about what (via what)?
3. The chemical signals (hormones) produced by the endocrine system are secreted into what or what? resulting in what?

Answer 1

1. homeostasis
2. rapid localized responses (via direct neural connections)
3. interstitium or blood; local affect or wide spread response respectively

Question 2

(Common Antomical features of endocrine organs)

1. Ducts or no?
2. cells are what in appearance? often arranged how?
3. sparse connective tissue
4. Vascular? often with what kinds of capillaries?

Answer 2

1. none
2. epitheloid; cords or clusters
3. -
4. yes - very much so; fenestrated (leaky) sinusoidal capillaries

Question 3

1. What modify the function of the “target” organs or cells?

2-5. What are the four structural groupoing of hormones?

Answer 3

1. hormones
2. peptides and proteins
3. steroids (testosterone, estrogen)
4. amino acid derivatives (thyroid hormones, epinephrine)
5. fatty acid derivatives - Eicosanoids (prostaglandins)

Question 4

1. Hormones typically bind specific hormone receptors located where in target cells?
2. Peptide type hormones… can they move through lipid membrane?
3. lipid nature hormones…. can they move through membranes? bind where?
4. The nuclear receptor activation results in what sequence?
5. Give me three paries of endocrine cells and their hormones…

Answer 4

1. on the surface or within (cytoplasm or nucleus) target cells
2. no - bind to surface cell receptor (use second messengers)
3. yes (plasma and nuclear); within target cell nucleus
4. transformation of receptor –> binding to chromosomal DNA –> activation of RNA polymerase –> and so on and so forth
5. beta cells of pancreas (insulin), interstitial cells of testis (tesosterone), follicular cells of ovary (estrogen)

Question 5

(Pituitary Gland (Hypophysis))

1. Pituitary gland sits in saddle-shaped depression of the what bone?
2. Connected to the hypothalamus by what?also Functionally connected via what (that picks up what)?
3. This gland has a complex and central role as a “relay station” - controlled by what thwo things?

Answer 5

1. spenoid bone (sella turcica)
2. a physical stalk of neural tissue (the infundibulum); vascular network (picks up hypothalamic derived neurosecretions)
3. brain and by feedback from target organs

Question 6

(Anatomical Divisions of Pituitary Gland)

1-2. What are the two divisions (plus give the embryologic origins)?

Answer 6

1. neurohypophysis (a brain outgrowth)
2. adenohypophysis (an oral cavity outgrowth)

Question 7

(The development of the pitutary gland)

1. The adenohypophysis develops as a pouch-like ectodermal outpocketing (hypophyseal cavity, aka Rathke’s pouch) from where?
2. The neurohypophysis develops as a downward extension from where?
3. The oral pouch surrounds the neural evagination as a what?
4. What will be the pars intermedia of the adenohypophysis?
5. The neural evagination that forms the neurohypophysis will remain physically connected to what?

Answer 7

1. the rood the stomodeum (oral cavity)
2. the floor of the hypothalamus (diencephalon)
3. double-layer (a remnant of the pouch cavity may persist)
4. the layer closest to the neurohypophysis
5. this original nervous tissue of the diencephalon (the hypothalamus)

Question 8

(Neurohypophysis)

1. aka what?
2. an extension of what?
3. What are transported to the neurohypophysis (where they are stored and released as needed)?

Answer 8

1. posterior lobe
2. the nervous system
3. HYPOTHALAMIC NEURON SECRETIONS

Question 9

(Median Eminence of Neurohypophysis)

1. Surrounds what?
2. What pass through the median eminence?
3. Axons terminals (Herring bodies) from the hypophysiotropic area of the hypothalamus secrete what?
4. These secretions are then carried to what via what to affect what?

Answer 9

1. infundibular recess (of the third ventricle)
2. Axons (going from the paraventricular and supraoptic hypthalamic nulcei to neural lobe - the hypothalamo-hypophyseal tract)
3. neurosecretory products (releasing/inhibitory factors) into this region
4. the pars distalis via a venous portal system (to affect pars distalis cells)

Question 10

(Infundibular stalk (or stem) of neurohypophysis)

1. primarily a what?
2. wat one specifically? from what areas of the hypothalamus?

Answer 10

1. _a nerve tract _
2. hypothalamo-hypophyseal tract from supraoptic and paraventricular areas of the hypothalamus

Question 11

(Neural Lobe of the Neurohypophysis)

1. aka what?
2. Contains what of hypothalamo-hypophyseal tract?
3. Some storage of what here?
4. The neural lobe is functionally connected to what two nuclei?

Answer 11

1. posterior lobe or pars nervosa
2. axons terminals (Herring bodies)
3. neurosecretory products
4. hypothalamic supraoptic and paraventricular nuclei

Question 12

(Neurosecretory products - hypothalamic origin)

1. What type are found in Herring bodies in the region of the Median Eminence?

Answer 12

1. Releasing and inhibitory factors (eg. growth hormone releasing hormone, growht hormone inhibiting hormone, thyrotropin releasing hormone, etc)

Question 13

(Neurosecretory products - hypothalamic origin)

1. What type are found in Herring bodies within the neural lobe?

* This hormone’s original name was vasopressin because it was observed that large (nonphysiologic) doses of the hormone resulted in contraction of the smooth muscle in vessel walls

2. Main affect of this hormone is related to what? Released in response to what?
3. What is the target (does what)?
4. What does a deficiency lead to?

Answer 13

1. ADH (antidiuretic hormone, aka vasopressin)

2. water homeostasis and osmolarity of body fluids; in response to decreased blood volume and/or increased osmolarity
3. kidney distal tubules and collecting ducts (increases H2O permeability of ductal cells)
4. nephrogenic diabetes insipidus

Question 14

(Neurosecretory Products (hypothalamic origin):

1. What type found in Herring bodies within the Neural Lobe?
2. Promotes what?
3. Targets what in female (+ does what)
4. Induces what kind of behavior in females?
5. In the male may function in what?

Answer 14

1. oxycotin
2. contraction of smooth muscle
3. mammary gland myoepithelial cells (promotes milk letdown) and uterine smooth muscle (aids parturition and sperm transport)
4. maternal behavior
5. ejaculation (eg. by acting on smooth muscle of ductus deferens and/or epididymis) and sexual arousal

Question 15

1. Stromal cell of neurohypophysis is the what?
2. helps do what?

Answer 15

1. pituicyte (an astroglial-like cell with many processes)
2. form structural support of structure

Question 16

1. What part of the Adenohypophysis surrounds part (infundibular stalk and median eminence) of neurohypophysis?

Answer 16

1. pars tuberalis

Question 17

1. What part of the adenohypophysis is located next to the neural lobe?
2. Separated from the larger pars distalis by what?
3. NOTE - large ruminants have a unique region of the pars intermedia that contains what?

Answer 17

1. the pars intermedia
2. a cavity (hypophyseal cavity; akak remnant of lumen of Rathke’s pocket)
3. “pars distalis” type cells called the cone of wulzen

Question 18

(Adenohypophysis)

1. Which part has a variety of cell types and is usually the largest part of the pituitary?
2. Where is it located?

Answer 18

1. pars distalis
2. adjacent to the hypophyseal cavity and/or intermediate….?

Question 19

(Pars Distalis)

1. Parenchyma consists of what types of cells containing what?
2. Cells are dispersed where?
3. There are how many cell types that produce and release how many hormones?

*Stroma is sparse connective tissue, and organ is highly vascular with fenestrated sinusoidal capillaries

Answer 19

1. clusters or cells of cords containing membrane bound granules
2. near the secondary capillary bed of the hypophyseal portal system
3. 5 cell types (tropes, “troph” - to nourish), 6 hormones (peptieds, polypeptides, glycoproteins)

Question 20

(Pars Distalis Cont)

1. Function is regulated by what? produced by what? which are where? released into where? then carried where?

Answer 20

1. hypothalamic hormones (releasing and inhibitory factors); produced by neurosecretory cells; in the hypothalamus; released into region of median eminence; carried to pars distalis (via hypphyseal portal system)

Question 21

(Classification of pars distalis cells)

1. stain-loving - acidophils and basophils
2. opposite
3. classification based on what?

Answer 21

1. chromophiles
2. chromophobes
3. histological staining

*however, identification of these cells require immunohistochemistry staining using antibody binding

Question 22

(Acidophils)

1. Stain how and produce what?
2. What are large cells organized into clusters? Contain what? These cells release what?
3. What is the function of somatotropin?

Answer 22

1. aciophillically and produce polypeptide hormones (2 major types)
2. Somatotropes; large membrane bound granules; somatotropin (= growth hormone)
3. promote grwoth (anabolic) and control of protein, lipid and carbohydrate metabolism

Question 23

1. What are solitary, round cells witha n eccentric nucleus that comprise 20-50% of the cell population of the pars distalis based on the sex and physiological status of the animal?
2. these cells contatin what?
3. What happens to these cells during pregnancy?
4. release what?
5. What does this promote? required for what in males? promotes what in many diverse species?

Answer 23

1. lactotropes or mammotropes
2. large membrane bound granules
3. increase in size and number
4. prolactin
5. milk production (lactation), late spermatogenesis, testis development, and release of androgens; promotes parental behavior

Question 24

(Basophils)

1. Stain how due to what? how many types?

Answer 24

1. basophilically due to content of glycoproteins (3 major types)

Question 25

(Basophils)

1. What type of basophils are pale, polyhedral cells with central nuclei and small membrane bound granules?
2. Are they the largest basophils?
3. What stimulates the secretion of thyroid hormones (thyroid follicular cells)?

Answer 25

1. thyrotropes
2. yes
3. Thyroid Stimulating Hormone (TSH) or thyrotropin

Question 26

(Basophils)

1. What type are pale cells with slight basophilia due to presence of non-secretory glycoprotein?
2. Have what type of granules that contain what?
3. A large precursor protein (called what?) is cleaved into what?
4. What stimulates the secretion of glucocorticoids - i.e. adrenal cortex (fasciculala and reticularis regions)?

Answer 26

1. corticotopes
2. small, peripheral membrane bound granules containg peptide hormones
3. (pro-opiomelanocortin or POMC); number of different hormones
4. Corticotropin or ACTH (adrenocorticotropic hormone)

Question 27

(Basophils)

1. What are small round to oval intensely basophilic cells that produce two glycoprotein hormones?
2. Both hormones in same cell or different?
3. Name the two hormones.

Answer 27

1. Gonadotropes
2. may be either
3. Follitropin (follicle stimulating hormone - FSH) and Lutropin (Luteinizing Hormone - LH)

Question 28

(Basophils)

(Gonadotropes)

1. What does Follitropin (Follicle Stimulating Hormone - FSH) simulate in females? in males?
2. What does Lutropin (Luteininzng Hormone - LH) stimulate in female? in male?

Answer 28

1. early follicle development; growth of seminiferous tubules and first phases of spermatogenesis
2. maturation of follicle, ovulation, corpus luteum development and progesterone secretion in the female; in male adrogen production by testis and late stages of spermatogenesis

Question 29

1. What are a small number of undifferentiated or reserve cells (possibly degranulated cells)?
2. small, round and have little cytoplasm
3. usually devoid of granules?
4. affinity for stains?

Answer 29

1. chromophobes
2. -
3. yes
4. little

Question 30

(Adenohypophysis)

(Pars Intermedia)

1. Pars Intermedia is separated from the pars distalis by what and is located adjacent to what?
2. How vascular is this part of adenohypophysis?
3. Clusters of P. intermedia cells may invade what?
4. Secretion is controlled by what?
5. Contains what two cell types?

Answer 30

1. hypophyseal cavity; neural lobe
2. not very
3. adjacent neurohypophysis
4. direct hypothalamic innervation
5. melanotropes and soem corticotropes

Question 31

(Pars Intermedia)

1. What are the most abundant parenchymal cell?
2. They produce what? ACTH is further cleaved to yield what?
3. Both of these are released in response to what?
4. In mammals, MSH has a role in what? amphibians?
5. What is in large ruminants is an area of pars distalis cells found within the pars intermedia and protrudes into the hypophyseal cavity?

Answer 31

1. melanotropes
2. POMC (similar to corticotropes); melanocyte stimulating hormone (MSH) and CLIP (coricotropin-like intermediate lobe peptide)
3. stress
4. general alertness, learning, memory; skin darkening
5. Wulzen’s cone

Question 32

1. What is located adjacent to median eminence and infundibular stalk? morphologically is an extension of what?
2. The portal venules of the hypophyseal portal system traverse what?
3. cells are mostly pale staining with a high density of what? what does this suggest? ultimately affects what?

*there are also a few gonadotropes and thyrotropes

Answer 32

1. pars tuberalis; pars distalis
2. the pars tuberalis
3. melatonin receptors; pars tuberalis acts as endocrine intermediate in photoperiodic effects of melationin on prolactin secretion; seasonal breeding cycles

Question 33

(HYPOPHYSEAL (VENOUS) PORTAL SYSTEM)

1. traverses the what?
2. Consists of how many capillary beds? where?

Answer 33

1. the neurohypophysis (median eminence) and adenohypophysis (pars tuberalis and distalis)
2. two; one in median eminence - other in pars distalis (connected by venules ie venous portal system)

Question 34

JUST READ HYPOPHYSEAL (VENOUS) PORTAL SYSTEM

on page 32

sorry