[Chapter 32] Endocrine Control Flashcards Preview

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Flashcards in [Chapter 32] Endocrine Control Deck (77)
1

Animal hormones

Cell products secreted from endocrine glands, endocrine cells, and a few neurons. In most cases, bloodstream circulates hormones to target cells

2

Neurotransmitters

Secreted by neurons into the tiny synaptic cleft between a neuron and a target cell

3

Local signaling molecules

Secreted by many cell types into extracellular fluid and broken down quickly; molecules only persist long enough to affect nearby tissues

4

Pheromones

Signals that diffuse through water or air to target cells in other individuals of the same species. Help integrate social behaviour (ex: female moth releases sex pheromone and attracts mate) Many vertabraes have vomeronasal organ in nose that responds to pheromones

5

When was the word hormone first used, what is its origin, and who coined it?

Early 1900s by physiologists W Bayliss and E Starling, from Greek word 'hormon', meaning 'to set in motion'

6

List the sources vertebrate hormones are (generally) secreted from

pituitary gland
adrenal gland (2)
pancreatic islets (numerous cell clusters)
thyroid gland
parathyroid gland (4 in humans)
pineal gland
thymus gland
gonads (2)
endocrine cells of the hypothalamus, stomach, small intestine, liver, kidneys, heart, placenta, skin, adipose tissue, and other organs

7

Endocrine system

All sources of hormones in the animal body, linked structurally and functionally with the nervous system in intercellular communication

8

How is the nervous system and the endocrine system linked?

Share a few structures, issue a few of the same signals, most organs accept and respond to signals from both.

9

In all animals, signaling molecules do what?

Integrate cell activities. each tupe of signal acts on all cells that have receptors for it. targeted cells may alter their activities in response.

10

Hypothalamus (part of the brain)

Produces, secretes six releasing and inhibiting hormones (act on different endocrine cells in anterior lobe of pituitary)

Produces ADH (conserves water) and oxytocin (roles in childbirth, milk secretion).

11

Pituitary gland, anterior lobe

ACTH, TSH, FSH, and LH (stimulate the secretion of other hormones), prolactine (affects mammary gland development), growth hormone (affects overall growth)

12

Pituitary gland, posterior lobe

Stores, secretes two hypothalamic hormones: ADH and oxytocin

13

Adrenal gland (one pair)
Cortex

Cortisol (affects glucose metabolism) and aldosterone (conserves sodium)

14

Adrenal gland (one pair)
Medulla

Epinephrine and norepinephrine (these hormones interact, in conert with the supathetic nervous system, to help adjust organ activities, especially during times of excitment or stress)

15

Ovaries (one pair of female gonads)

Estrogens and progesterone (maintain primary sex organs, influence secondary sexual traits)

16

Testes (one pair of male gonads)

Testosterone (develops and maintains primary sex organs, influences secondary sexual traits)

17

Pineal gland

Melatonin (affects biological clocks, overall level of activity, reproductive cycles)

18

Thyroid gland

Thyroid hormone (affects growth and development, metabolism), calcitonin (lowers blood level of calcium)

19

Parathyroid glands (four)

Parathyroid hormone (increases blood level of calcium)

20

Thymus gland

Thymosins (roles in white blood cell functioning)

21

Pancreatic islets

Insulin (lowers blood level of glucouse), glucagon (raises blood level of glucose)

22

Hormones induce changes in service of programs of...

Growth, maintenance, and reproduction

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Three steps of cell communication

Signal Reception (signal activates target cell receptor), signal transduction (transduced to a molecular form that acts in the receiving cell), cellular response (cell may make a functional response)

24

What do enzymes do?

Make hormones from a variety of sources

25

Steroid hormones are derived from?

Cholesterol
ex: testosterone and other androgens, estrogens, progesterone, aldosterone, cortisol

26

Amine hormones are?

Modified amino acids
ex: melatonin, epinephrine, thyroid hormone

27

Peptide hormones are?

Short chains of amino acids
ex: glucagon, oxytocin, antidiuretic hormone, calcitonin, parathyoid hormone

28

Protein hormones are?

Longer chains of amino acids
ex: growth hormone, insulin, prolactin, follicle-stimulating hormone, luteinizing hormone

29

Signal response requires?

Functional receptors

30

Second messenger

A molecule that is formed in response to an external signal and causes more cellular changes

31

What kind of things influence hormone action?

Type/state of target receptors, interventions by other hormones, feedback mechanisms, environmental cues, etc
More specifically...
1. Cells need the right receptors for specific hormones
2. Different hormones often interact. Binding of one hormone may block, enhance, or have no effect on the cell's response to other hormones
3. Concentration of particular hormone in tissue. More hormone molecules in the interstitial fluid around target cell, more likely to bind with receptors
4. Target cell's metabolic and nutritional state
5. Specific environmental cues like temperature, day length, etc

32

How do hormone molecules interact with receptors on/in target cells?

they reversibly bind

33

How do steroid and thyroid hormones bind to change gene expression?

With receptors insider the cell

34

How do steroid and thyroid hormones bind without changing gene expression?

With receptors at the cell surface, triggers fast responses

35

How do peptide and protein hormones bind?

to membrane receptors. often, second messenger in cytoplasm relays signal to cell's interior

36

Hypothalamus

Forebrain region, has neurons that secrete hormones

37

Pituitary gland

Attached by a stalk of tissue to the hypothalamus. in humans, no bigger than a pea.

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Posterior lobe of pituitary gland

stores and secretes hormones from hypothalamus

39

Anterior lobe of pituitary gland

Makes own hormones, signals from hypothalamus control their release

40

How do the hypothalamus and the pituitary gland work together?

Interacts as a master control center, integrating much of the activity of the endocrine and nervous systems

41

Releasers

Call for the secretion of hormones by target cells

42

Inhibiters

discourage target cell secretions

43

ACTH

stimulates the release of cortisol from a pair of adrenal glands

44

TSH

stimulates the release of thyroid hormones from the thyroid gland

45

FSH and LH

affect gamete formation in the reproductive organs and other aspects of sexual reproduction

46

GH

growth hormone, has targets in most tissues. triggers secretions from liver cells that promote growth of bone and soft tissues in the young, influences metabolism in adults

47

PRL

initiates and maintains milk production in mammary glands after other hormones prime the tissues

48

Thyroid Gland

Anterior base of the beck, secretes calcitonin and thyroid hormone, which is a ix of two amines

49

Thyroid hormone

Central to metabolism and development

50

How is the thyroid gland controled?

By the anterior pituitary and hypothalamus, through negative feedback loops

51

Parathyroid glands

Four of them on the posterior surface of the thyroid, secrete PTH. Main control over the calcium in blood

52

PTH

parathyroid hormone, stimulates the breakdown of bone, decreases calcium loss in urine, and activates the vitamin D needed to absorb calcium from food.

53

Vitamin D and PTH

PTH activates vitamin D needed to absorb calcium from food, thus, PTH increases blood calcium. Vitamin D deficiency lowers calcium level in blood, which leads to oversecretion of PTH and bone breakdown

54

Adrenal Glands

Humans have a pair of adrenal glands, one on top of each kidney.

55

Adrenal cortex

Outermost part of adrenal glands, releases steroid hormones

56

Aldosterone

Controls sodium and water reabsorption in the kidneys, released by adrenal glands

57

Cortisol

Released by adrenal glands, affects metabolism and immune responses, maintains blood level of glucose, induces liver cells to break down their store of glycogen, supresses uptake of glucose by other cells. induces adipose cells to degrade other fats, and skeletal muscles to degrade proteins, makes immune responses wind down. controled by negative feedback loop

58

When and by what is the cortisol feedback loop overridden?

The nervous system overrides it during times of injury, illness, anxiety. this leads to very high levels of cortisol

59

Adrenal medulla

Inner part of adrenal gland, secretes norepinephrine and epinephrine during times of stress, excitement, or danger.

60

Norepinephrine and epinephrine

Same effects on targets that sumpathetic nerves do, bring about fight-or-flight response

61

Long term elevation of cortisol levels?

Disrupts production and release of other hormones, suppress immune function, impair memory. impact can be seen in people with Cushing syndrome

62

Pancreas

in abdominal cavity behind the stomach, has exocrine (scretes digestive enzymes into duct to small intestine) and endocrine functions (clusters called pancreatic islets, contains three types of hormone-secreting cells)

63

Alpha cells

Secrete the peptide hormone glucagon. between meals, all cells take up glucose from blood. When glucose level falls below set point, alpha cells secrete glucagon, which binds cells int he liver and causes activation of enzymes that break glycogen into glucose subunits. Raises level of glucose in the blood

64

Beta cells

Most abundant cells in pancreatic islets, secrete insulin, the only hormone that causes target cells to take up and store glucose. Releases insulin after stimulated by higher blood level of glucose

65

Delta cells

Secretes somatostatin, helps control digestion and nutrient absorbtion. Can inhibit the secretion of insulin and glucagon

66

Diabetes mellitus

Metabolic disorder in which cells do not take up glucose as they should, in result, sugar accumulates in blood and urine. This encourages growth of pathogenic bacteria, damages small blood ells in kidneys, permanent kidney failure. Uncontrolled diabetes also damages blood vessels and nerves, especially in arms, hands, legs, and feet

67

Type I Diabetes

Develops after the body has mounted an autoimmune response against is insulin-secreting beta cells. Most dangerous type of diabetes short term. In absence of glucose, the body uses fats and proteins as energy sources. Two outcomes are weight loss and ketone accumulation in the blood and urine. Can interfere with brain funtion, extreme causes may lead to coma or death

68

Type II Diabetes

More common form of disorder. Insulin levels are normal or high but target cells do not respond to the hormone as they should and blood sugar levels remain high. If glucose lvels are not lowered, pancreatic beta cells continue to receive continual stimulation and they will eventually falter

69

Hypoglycemia

Blood glucose level falls low enough to disrupt normal body functions. Rare insulin-secreting tumours can cause it, but usually after insulin-dependent diabetic miscalculates and injects too much insulin to balance food intake. Results in insulin shock, brain stalls as its fuel dwindles. Can be lethal, but injection of glucagon reverses condition

70

Gonads

Male = testes, females = ovaries. produces gametes and secrete sex hormones, including estrogens and androgens

71

Puberty

Post-embyronic stage of development when the reproductive organs and structures mature

72

Estrogen in males

Develops sperm

73

Testosterone in females

Affects libido

74

Pineal Gland

Depp inside the vertabrate brain. Secretes melatonin, which serves as part of internal timing (biological clock, rate of secretion varies depending on amount of light brain is responding to.

75

Thymus gland

Lies beneath breastbone, secretes hormones that help infection-fighting white blood cells (T cells) to mature, grows until person reaches puberty, when the surge in sex hormones causes it to shrink and its secretions decline

76

How did vertabrates evolve so many diverse hormones and hormone receptors?

Molecular evidence points to gene duplications and subsequent divergences through mutations

77

Ecdysone

Steroid hormone, controls molting in nematodes and arthropods, influences by environmental cues