Bisc 125 Neuroendocrine System

Front 1

What are the two embryological portions of the pituitary gland?

Back 1

The adenohypophysis and the neurohypophysis

Front 2

Which part of the pituitary gland is the epithelial, glandular portion?

Back 2

The adenohypophysis

Front 3

What are the three parts of the adenohypophysis?

Back 3

The pars distalis (hormone center), pars intermedia, and pars tuberlis

Front 4

What part of the brain stimulates the pituitary gland?

Back 4

The hypothalamus

Front 5

What are the parts of the neurohypophysis?

Back 5

The pars nervosa (a "downgrowth" of the brain), infundibular process and median eminence(extension of the hypothalamus)

Front 6

What path do inhibiting and releasing factors take in the hypothalamic/hypophyseal portal system?

Back 6

Factors produced in the hypothalamus enter fenestrated capillaries, which go into veins (portal veins), which bring the factors to the pars distalis, where veins turn into fenestrated capillaries, where the factors leave the capillaries and affect the appropriate cell

Front 7

How does the hypothalamic/hypophyseal tract work?

Back 7

It is NON-VASCULAR; neuroendocrine hormones travel from the hypothalamic nuclei down microtubules in axons which travel from the nuclei to the pars nervosa

Front 8

What are the three components of the adenohypophysis (specifically the pars distalis)?

Back 8

Supportive cells, endocrine cells, and fenestrated capillaries

Front 9

What are the three types of cells in the pars distalis?

Back 9

Acidophils (90% of chromophils), basophils (10% of chromophils), and chromophobes(50% of total cells)

Front 10

What do acidophils secrete?

Back 10

Growth hormone and prolactin

Front 11

What do basophils secrete?

Back 11

Gonadotropins (FSH and LH), thyroid stimulating hormone (TSH), and adrenal corticotropic hormone (ACTH)

Front 12

How does growth hormone work?

Back 12

It stimulates hepatocytes (targets liver) to secrete somatomedin C, which stimulates growth

Front 13

How is growth hormone released?

Back 13

In pulses throughout the day, with its peak time just before waking

Front 14

What are the two hormones that regulate growth hormone?

Back 14

Growth hormone releasing hormone(GHRH)is stimulatory, somatostatin is inhibitory.

Front 15

What hormone is the main inhibitor of prolactin?

Back 15

Dopamine

Front 16

What does prolactin do?

Back 16

It targets the mammary glands, stimulating the ductal and secretory portions; stimulates milk sythesis and lactation

Front 17

When is prolactin important?

Back 17

During puberty, pregnancy, and lactation

Front 18

What can result from too much prolactin?

Back 18

Infertility in males and females and erectile dysfunction in men

Front 19

What does follicle stimulating hormone (FSH) do?

Back 19

In females, stimulates ovarian follicle development; in males, stimulates Sertoli cells in testes to produce androgen binding protein

Front 20

What does lutenizing hormone (LH) do?

Back 20

In females, stimulates steroidgenesis in the ovarian follicles and corpus luteum; in males, regulates testosterone production (controls rate of production by Leydig cells)

Front 21

About how many anterior hypophysial cells are TSH secreting cells?

Back 21

About 5%

Front 22

What does thyroid-stimulating hormone do?

Back 22

Regulates the function and growth of thyroid; can also affect bone growth and metabolic rate

Front 23

What portion of the adrenal cortex is stimulated by ACTH?

Back 23

The zona fasciculata and zona reticularis

Front 24

What cells are stimulated by ACTH?

Back 24

Cortisol-producing cells

Front 25

What hormone is associated with the release of B-lipotropic hormone, B-endorphin, and B-msh?

Back 25

Adrenal corticotropic hormone

Front 26

What is the relationship between ACTH and the circadian rhythm?

Back 26

ACTH release peaks in the morning and slowly declines the rest of the day.

Front 27

How does the neurohypophysis receive neurosecretory substances from the hypothalamic nuclei?

Back 27

Via the hypothalamic/hypophyseal tract

Front 28

What is a Herring body?

Back 28

Droplets of hormone that are transported into fenestrated capillaries located in the pars nervosa

Front 29

What are the three main components of the pars nervosa?

Back 29

Axons carrying neurosecretory material, supportive cells (pituicytes), and fenestrated capillaries

Front 30

What cells in the pituitary resemble astrocytes in the CNS?

Back 30

Pituicytes

Front 31

How do pitiuicytes work?

Back 31

They act as supporting cells; prevent hormones from getting out into the surrounding tissue until it reaches the fenestrated capillaries

Front 32

From where do the microtubules in axons transport neurosecretory material?

Back 32

From the supraoptic and paraventricular nuclei in the hypothalamus

Front 33

What hormones from the hypothalamus are released in the pars nervosa?

Back 33

Antidiuretic hormone (ADH) and oxytocin

Front 34

What does ADH do?

Back 34

Brings about resorption of water in the collecting tubule of the kidney; can also elevate BP during severe blood loss by forcing arteries to clamp down

Front 35

What does oxytocin target?

Back 35

Myoepithelial cells of the mammary gland and the smooth muscle of the uterine wall; can be used to induce labor

Front 36

Where is the pineal gland located?

Back 36

In the third ventricle of the brain

Front 37

How does the pineal gland maintain contact with the brain?

Back 37

Via postganglionic sympathetic nerve fibers (no direct connection, despite close proximity)

Front 38

What are the supportive cells of the pineal gland?

Back 38

Glial-type cells; interstitial cells support pinealocytes

Front 39

How are pinealocytes organized?

Back 39

Into cords and clusters on the basal lamina, surrounded by C.T.

Front 40

What do pinealocytes secrete?

Back 40

Melatonin

Front 41

How does melatonin influence the sleep cycle?

Back 41

Darkness stimulates the production of melatonin; it's at its highest content during the night (synthesized from tryptophan, makes people sleepy)

Front 42

What is corpora arahacea?

Back 42

Also known as brain sand; is calcified granules that accumulate in the brain and pineal gland as people age

Front 43

What is precocious puberty?

Back 43

When children become sexually mature by eight years old for girls, and eight or nine years old for boys; caused by a tumor in the pineal gland and is usually fatal