Chapter 17 - Endocrine System

Front 1

What are the four principle avenues of communication from cell to cell? pg. 634

Back 1

• Gap Junction
• Neurotransmitters
• Paracrines
• Hormones

Front 2

What does a Gap junction do? pg. 634

Back 2

Join single-unit smooth muscle, cardiac muscle, epithelial, and other cells. Enable cells to pass nutrients, electrolytes, and signaling molecules from cytoplasm of one cell to that of the next through pores in the plasma membrane.

Front 3

What do neurotransmitters do? pg. 634

Back 3

Released by neurons, diffuse across a narrow synaptic cleft, and bind to receptors on the surface of the next cell.

Front 4

What do paracrines do? pg. 634

Back 4

Secreted by one cell, diffuse to nearby cells in the same tissue, and stimulate their physiology. Some call them local hormones.

Front 5

What do Hormones do? pg. 634

Back 5

In the strict sense are chemical messengers that are transported by the bloodstream and stimulate physiological responses in cells of another tissue or organ, often a considerable distance away. I.e. Hormones produced in pituitary gland act on organs in the pelvic cavity.

Front 6

Define endocrine system: pg. 634

Back 6

The glands, tissues, and cells that secrete hormones.

Front 7

Name the area that studies the endocrine system and diagnosis and treats disorders. pg. 634

Back 7

Endocrinology

Front 8

Name some endocrine glands that secrete hormones? Can an organ secrete hormones? pg. 634

Back 8

Pituitary, thyroid, and adrenal glands. Hormones are also secreted by organs and tissues not thought of as glands such as the brain, heart, small intestines, bones, and adipose tissue.

Front 9

What is the difference between an exocrine gland and an endocrine gland? pg. 634

Back 9

The distinction is the presence or absense of ducts. Most exocrine glands secrete their products by way of a duct onto the skin's surface. Endocrine glands are ductless and release secretions into the bloodstream.

Front 10

Which secretion has extracellular /intracellular effects? pg. 635

Back 10

Exocrine secretions have extracellular effects (digestion of food). Endocrine secretions have intracellular effects (alter cell metabolism).

Front 11

What type of dense capillaries are specific to endocrine glands? pg. 635

Back 11

Fenestrated capillaries are especially permeable and serve to pick up and carry away hormones. They have patches of large pores in their walls allowing for easy uptake of matter from gland tissue.

Front 12

Can a gland or secretory cell act as an endocrine and exocrine? provide an example? pg. 635

Back 12

Liver cells behave as exocrine cells by secreting bile into ducts that lead ultimately to the small intestine. However, they also secrete hormones, albumin, & blood clotting factors into the blood, acting like and endocrine cell.

Front 13

How do liver secretions work differently than traditional exocrine/endocrine glands? Pg. 635

Back 13

They are not released by way of ducts or onto epithelial surfaces. Nor do they fit the concept of endocrine secretions, because they are not hormones.

Front 14

Compare and contrast nervous/endocrine system. pg. 636

Back 14

Nervous Syst: Communicates with electrical impulse
Endocrine Syst: Communicates with hormones
Nervous Syst: Releases neurotransmitters at synapse of target cell.
Endocrine Syst: Releases hormones into bloodstream for general distribution throughout body.
Nervous Syst: Usually has local, specific effects
Endocrine Syst: general widespread effects
Nervous Syst: Reacts quickly to stimuli
Endocrine Syst: Reacts slowly to stimuli, sometimes days
Nervous Syst: Stops quickly when stimulus stops
Endocrine Syst: May continue responding
Nervous Syst: Adapts quickly to continual stimulation
Endocrine Syst: Adapts slowly days to weeks

Front 15

What are the three parts to the neurohypophysis?

Back 15

The median eminence (an extension of the floor of the brain; the infundibulum, the largest part, the posterior lobe (pars nervosa).

Front 16

Is the neurohypophysis a gland?

Back 16

No it is nervous tissue (nerve fibers arise from certain cell bodies in the hypothalamus and pass down the stalk as a bundle called the hypothalamo-hypohyseal tract, and end in the posterior lobe.

Front 17

Where are hormones made? How do they get moved to the posterior pituitary?

Back 17

Hormones are made in the hypothalamic neurons and move down the nerve fibers by axoplasmic flow to the posterior pituitary. Here they are stored in the nerve endings until a nerve signal coin down the axon triggers a release.

Front 18

There are 8 hormones produced in the hypothalamus (6 to regulate the anterior pituitary and two that are stored in the posterior pituitary and released on demand). Can you name them?

Back 18

First 6
Follicle-stimulating hormone (FSH), Luteinizing hormone (LH), Thyroid-stimulating hormone (TSH), Adrenocorticotropic hormone (ACTH), Prolactin (PRL), Growth Hormone (GH)
Remaining 2: antidiuretic hormone (ADH), Ocytocin (OT)

Front 19

Name the target organ or tissue and the principle effects of the follicle-stimulating hormone (FSH)?

Back 19

•Ovaries, testes
•Female: growth of ovarian follicles and secretion of estrogen
•Male: sperm production.

Front 20

Name the target organ or tissue and the principle effects of the Luteinizing hormone (LH)?

Back 20

•Ovaries, testes
•Female: ovulation, maintenance of corpus luteum
•Male: testosterone secretion

Front 21

Name the target organ or tissue and the principle effects of the Thyroid-stimulating hormone (TSH)?

Back 21

•Thyroid Gland
•Growth of thyroid, secretion of the thyroid hormone

Front 22

Name the target organ or tissue and the principle effects of the Adrenocorticotropic hormone (ACTH)?

Back 22

•Adrenal cortex
•Growth of adrenal cortex, secretion of glucocorticoids

Front 23

Name the target organ or tissue and the principle effects of Prolactin (PRL)?

Back 23

• Mammary glands, testes
• Female: milk synthesis
• Male: Increased LH sensitivity

Front 24

Name the target organ or tissue and the principle effects of Growth hormone (GH)?

Back 24

• Liver, bone, cartilage, muscle, fat
• Widespread tissue growth, especially in stated tissues.

Front 25

Name the target organ or tissue and the principle effects of Antidiuretic hormone (ADH)?

Back 25

• Kidneys
• Water retention

Front 26

Name the target organ or tissue and the principle effects of Oxytocin (OT)

Back 26

• Uterus, mammary glands
• Labor contractions, milk release; possible involved in ejaculation, sperm transport, sexual affection and mother-infant bonding.

Front 27

What are the principle effects of Thyrotropin-releasing hormone (TRH)?

Back 27

Promotoes secretion of thyroid-stimulating hormone (TSH) and prolactin (PRL)

Front 28

What are the principle effects of Corticotropin-releasing hormone (CRH)?

Back 28

Promotes secretion of adrenocorticotropic hormone (ACTH)

Front 29

What are the principle effects of Gonadotropin-releasing hormone (GnRH)?

Back 29

Promotes secretion of follicle-stimulating hormone (FSH) and luteinizing hormone (LH)

Front 30

What are the principle effects of Growth hormone-releasing hormone (GHRH)?

Back 30

Promotes secretion of growth hormone (GH)

Front 31

What are the principle effects of Prolactin-inhibiting hormone (PIH)?

Back 31

Inhibits secretion of prolactin (PRL)

Front 32

What are the principle effects of Somatostatin?

Back 32

Inhibits secretion of growth hormone (GH) and thyroid-stimulating hormone (TSH)

Front 33

Define releasing hormones?

Back 33

Hormones that stimulate pituitary cells to secrete hormone of their own.

Front 34

Define inhibiting hormones?

Back 34

Hormones that suppress pituitary secretion.

Front 35

Name the two gonadotropin hormones? Why are they called this?

Back 35

• Follicle-stimulating hormone (FSH) – secreted by pituitary cells called gonadotropes.
• Luteinizing hormone (LH) – Secreted by gonadotropes.
• They are called gonadotropin because they target the ovaries and testes (gonads)

Front 36

What type of cell secretes the thyroid-stimulating hormone (TSH)?

Back 36

• Thyrotropes.
• This hormone has a widespread effect on metabolic rate, body temperature, and other functions.

Front 37

What type of cell secretes Adrenocorticotropic hormone (ACTH)?

Back 37

Corticotropes

Front 38

Which hormone secretes cortisol? What is cortisol?

Back 38

•Adrenocorticotropic hormone (ACTH)
•Cortisol regulates glucose, protein, and fat metabolism and are important to the bodies response to stress.

Front 39

What type of cell secretes Prolactin (PRL)?

Back 39

• Lactotropes (mammotropes)

Front 40

What type of cell secretes Growth hormone (GH)?

Back 40

•Somatotropes, the most numerous cells of the anterior pituitary.
•The general effect of GH is to stimulate mitosis and cellular differentiation and thus to promote tissue growth.

Front 41

What is absent from an adult human pituitary, but present in other animals and the human fetus?

Back 41

Pars intermedia

Front 42

What does the Pars intermedia secrete in other species, what does this hormone do?

Back 42

•Melanocyte-stimulating hormone (MSH)
•It influences pigmentation of the skin, hair, or feathers.

Front 43

What is the function of the antidiuretic hormone (ADH)?

Back 43

•Increase water retention by the kidneys, reduces urine volume, and helps to present dehydration.
•Can also act as a brain neurotransmitter and is usually called arginine vasopressin (AVP) because it can cause vasoconstriction, but this effect requires extremely high concentrations, so it isn’t significant.

Front 44

What is the function of Oxytocin (OT)?

Back 44

A variety of reproduction functions. It surges in sex, during arousal and orgasm, possibly aiding the propulsion of semen. It stimulates uterine contractions. In its absence other female mammals neglect young.

Front 45

Are hormones constantly secreted? Give examples

Back 45

•They are not secreted at constant rates. GH is secreted at nigh, LH peaks at the middle of the menstrual cycle, and OT surges during labor and nursing.
•The timing and regulation are controlled by the hypothalamus.