18.6-18.9 Flashcards Preview

BIO 142-ch. 18 > 18.6-18.9 > Flashcards

Flashcards in 18.6-18.9 Deck (26):
1

Pituitary gland (hypophysis)

The master endocrine gland that controls other glands. Pea shaped structure that lies in hypophyseal fossa and has two regions: anterior and posterior pituitary.

2

Hypothalamus

Controls the pituitary gland. Major link between nervous and endocrine system. Synthesizes 9 different hormones.

3

Infundibulum

Funnel. Composed of anterior and posterior pituitary.

4

anterior pituitary

75% of pituitary weight.
Secretes hormones to regulate growth and reproduction.

Composed of epithelial tissue.

composed of two parts:

1)pars distalis
2) pars tuberalis

5

Pars tuberalis

Part of anterior pituitary. Forms sheath around infundibulum.

6

Posterior pituitary

Composed of neural tissue. Consists of two parts.

1)pars nervosa
2) pars intermedia

7

Hypophyseal portal system flow of order

Superior arteries>primary plexus>veins>secondary plexus

8

Neurosecretory cells

Synthesize the hypothalamic releasing and inhibiting hormones

9

Tropic hormones (tropins)

Anterior pituitary hormones that act on other endocrine glands

10

Hormones of the anterior pituitary:

Somatotrophs
Thyrotrophs
Gonadotropins
Lactotrophs
Corticotrophs

11

Somatotrophs

Secrete HGH, Aka somatotropin. Which then stimulates release of insulin growth factors (iGF)

12

Thyrotrophs

Thyroid stimulating hormone, aka thyrotropin.

13

Gonadotrophs

Aka gonadotropins, 2 kinds-
1) follicle stimulating hormone (FSH)
2) luteinizing hormone (LH)

Produce estrogen in ovaries and testosterone in testes.

14

Lactotrophs

Secrete prolactin (PRL) which starts milk production in mammary glands.

15

Corticotrophs

Secrete adrenocorticotropic hormone (ACTH) aka corticotropin . Stimulates secretion on cortisol or melanocyte-stimulating hormone (MSH).

16

Functions of IGF

1) increase uptake of amino acids accelerating protein synthesis

2)enhance lipolysis

3) increase carb metabolism by decreasing glucose uptake

17

Hypoglycemia

Low blood glucose concentration

18

Hyperglycemia

High blood glucose concentration , stimulates hypothalamus to secrete GHRH

19

Posterior pituitary

Does not synthesize hormones, but stores and releases two hormones: oxytocin (OT) & antidiuretic hormone (ADH)

20

Blood flow of posterior pituitary

Inferior hypophyseal arteries>capillary plexus of infundibular process> posterior hypophyseal veins>distribution to target cells

21

Oxytocin

Affects uterus and breasts. Allows for smooth muscle to contact during labor and for lactation for breast feeding.

22

Antidiuretic

Decreases urine production . Causes kidneys to return more water to the blood.

Fun fact: alcohol inhibits secretion of ADH.

23

Vasopressin

An antidiuretic which raises blood pressure

24

Osmoreceptors

Neurons in Hypothalamus that monitor blood osmotic pressure

25

Blood carries ADH to three target tissues

Kidneys, sweat glands, smooth muscle in blood vessel walls

26

Hypothalamohypophyseal tract

Begins in the hypothalamus and ends near blood capillaries in posterior pituitary