Human Biology Endocrine System- Lakeland Community College

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1

What stimulates the endocrine glands?

other hormones, humoral levels of a substance ( such as glucose or calcium), and nerve impulses

2

What kinds of processes do hormones control?

1. reproduction and growth development

2. mobilization of body defenses

3. regulation of metabolism

3

What is the function of the Endocrine system?

To secret hormones into the tissue, which secretes into the blood

4

Where are hormones produced?

by endocrine glands

5

How do Endocrine glands secrete hormones?

Endocrine glands secrete hormones into extracellular fluids

6

What are hormones?

chemical signals that affect other glands or tissues

7

What do hormones do?

regulate activity of cells elsewhere in the body

8

What are the possible effects of hormones on target cells?

1. metabolism

2. growth and development

3. homeostasis

9

What are target cells?

cells that hormones act on. They have specific hormone receptors and respond when the hormone binds onto them

10

Where do hormones travel?

throughout the bloodstream

11

What are the two hormone categories?

1. amino-acid hormones (peptide hormones)

2. steroid hormones

12

How are amino-acid hormones different in their function?

amino-acid hormones (first messengers) binds to a receptor on the cell membrane because the hormone cannot enter the cell.

amino-acid hormones are not lipid soluble

13

How do amino acid hormones signal inside the cell?

They activate an enzyme that produces a second-messenger molecule inside the cell, which has an effect within the cell

14

How is the release of hormones maintained?

negative feedback system; when appropriate levels are reached, hormone release stops

15

How do steroid hormones move through the cell?

Diffusion; steroids are lipid-soluble

16

List the major type of hormones found in the body

hypothalamus

pituitary gland

parathyroid glands

adrenal glands

pineal gland

thymus gland

pancreas

gonads

17

What is a second messenger system?

molecules that relay signals received at receptors on the cell surface

18

Describe the function of an amino acid hormone (peptide hormone)

binds to the receptor protein on the plasma membrane and activates a second messenger system

** this leads to a large cellular response**

19

What types of hormones are steroids?

sex hormones and adrenal cortex hormones

20

What do steroid hormones do in the nucleus?

They bind to protein receptors: the receptor and protein then bind to the cell's DNA and activate genes, causing new proteins to synthesize

21

Describe the action of a steroid hormone

to bind to receptor proteins, this creates a hormone-receptor complex. the hormone receptor complex binds to DNA, activating particular genes. gene activation leads to the production of cellular enzymes that cause cellular changes

22

Describe hormonal stimulation of Endocrine glands

HINT: 3 different ways

1. humoral - concentration of dissolved substances or ions in the blood

2. by the actions of other hormones that stimulate of inhibit its release

3. the nervous system can make adjustment to maintain homeostasis

23

What are the major Endocrine glands?

hypothalamus

pituitary gland

thymus gland

adrenal gland

gonads

pancreas

thyroid gland

pineal gland

parathyroid glands

24

What is the function of the hypothalamus?

The hypothalamus is the link between the nervous and endocrine systems

25

What is the function of the antidiurectic hormone (ADH)

Inhibits urine production (diuresis) by promoting water reabsorption of the kidneys (decreases urine volume, and increases blood volume) --> blood salt concentration is high

** controlled via negative feedback mechanisms**

location: posterior pituitary

26

What is another name for vasopressin?

antidiuretic hormone (ADH)

27

What is the function for oxytocin?

- stimulates uterine contractions during childbirth

- causes milk ejection in nursing women

location: posterior pituitary

28

What are the two parts of the pituitary gland?

posterior pituitary gland ( neurohypophysis)

anterior pituitary gland ( adenohypophysis)

29

What are the two hormones made in the hypothalamus, but stored in and released from the posterior pituitary?

1. oxytocin

2. antidiuretic hormone

30

Describe an ADH disorder

Diabetes insipidus: a condition which causes polydipsia and hyposecretion of ADH

31

What specific hormone acts on the anterior pituitary?

thyrotropin (TRH) -- releasing hormone

gonadotropin (GnRH) -- releasing hormone

corticotropin (CRH) -- releasing hormone

growth hormone (GHRH) -- releasing hormone

somatostatin -- inhibiting hormone

dopamine: prolactin inhibiting hormone and neurotransmitter

32

What inhibits the secretion of ADH?

alcohol --> can cause increased urine output and dehydration

33

What type of cells make ADH and oxytocin?

neurosecretory cells

34

What are the six anterior pituitary hormones?

1. tropic hormones : stimulates other endocrine glands

2. growth hormone and prolactin : affect the body directly

3. thyrotropic hormone

4. adrenocorticotropic hormone

5-6. gonadotropic hormones

35

What is the function of the thyroid stimulating hormone (TSH)?

it influences the growth and activity of the thyroid gland, which stimulates metabolism

36

What is the function of the adrenocorticotropic hormone (ACTH)?

promotes secretion of the adrenal cortex hormones (stress respondents). Stimulated by corticotropin- releasing hormone from the hypothalamus

location: anterior pituitary

37

Describe gonadotropic disorders

Hyposecretion of FSH or LH leading to sterility in both males and females but hypersecretion does not appear to cause any problems

38

What are the two types of gonadotropic hormones?

FSH and LH --> regulation of hormonal activity of the gonads

39

Differentiate between FSH and LH

FSH: follicle stimulating hormones - stimulate follicle (egg) development in ovaries (secrets estrogens) and stimulates sperm development in testes

LH: luteinizing hormone - triggers ovulation of an egg in females (secrets progesterone) and stimulates testosterone production in males

location: anterior pituitary

40

What is the function of prolactin (PRL)?

stimulates and maintains milk production following childbirth. it works with oxytocin which allows the release of milk

location: anterior pituitary

41

What are the three growth hormone disorders?

1. pituitary dwarfism: hyposecretion of GH during childhood. the body proportions are normal, but the person does not grow taller than 4 ft tall

2. gigantism: hypersecretion of GH during childhood. Individual reaches 8-9 ft tall

3. acromegaly: hypersecretion of GH during adulthood. The long bones have stopped growing, which causes enlargement of lower jaw, brow, ridges, feet and hands

42

What is the purpose of the growth hormone?

determines the final body size by affecting the growth of bones and muscles.

also acts as a general metabolic hormone by promoting protein synthesis, fat breakdown and the maintenance of blood glucose homeostasis

43

Where is the thyroid gland found?

at the base of the throat

44

What is a goiter?

homeostatic imbalance when the thyroid gland enlarges due to a lack of iodine-thyroxine, negative feedback fails, thus preventing TSH production

45

What two hormones does the thyroid gland produce?

1. thyroid hormone

2. calcitonin

46

What is the thyroid gland composed of?

thyroxine (T4) - secreted by thyroid follicles

triiodothyronine (T3) - deals with conversion of T4 at target cells

47

What is the purpose of the thyroid hormone?

it controls the rate at which glucose is converted to body heat and chemical energy

*** every cell is a target***

48

List disorders of the thyroid hormone

1. congenital hypothyroidism --> the thyroid fails to develop properly occurring at birth. Individuals are usually short and stocky

2. Myxedema --> hypothyroidism in adults. Characterized by lethargy, weight gain, hair loss, slower pulse rate, lowered body temperature, thick and puffy skin

3. hyperthyroidism --> oversecretion of the thyroid hormone

49

What is an exophthalmic goiter?

edema in eye socket tissues. this causes swelling in the muscles that move the eyes

s/s:hyperactivity, anxiousness and irritability and insomnia

tx: surgical removal or destruction of part of the thyroid by radioactive iodine

50

What is Graves' disease?

an autoimmune disease characterized by s/s of cardiovascular disease, increased body temperature, fatigue, weight loss, depression, and mental confusion

51

What is the purpose of calcitonin?

decreases blood calcium levels

causes deposition on bone

**antagonistic to parathyroid hormone**

** production decrease in adulthood**

52

What is the purpose of the parathyroid glands?

to secrete parathyroid hormone (PTH) to raise calcium levels in the blood

1. stimulates calcium removal from bone

2. stimulates kidneys and intestines to absorb more calcium

3. activates vitsmin D (calcitriol) in the kidneys, which stimulates the reabsorption of calcium in the intestines

53

What happens if blood calcium levels fall too low?

parathyroid hormones releases PTH into the bones. Bones release calcium into the blood, kidneys reabsorb calcium from kidney tubules, intestines absorb calcium from digestive tract. blood calcium then rises

*hypocalcemia --> tetany (continual muscle spasms) results when there is insufficient secretion of PTH and blood calcium levels are low

54

What happens if blood calcium levels rise?

thyroid hormone secrets calcitonin in to the blood. bone absorbs calcium from the blood and than blood calcium lowers

*hypercalcemia --> can be due t o PTH oversecretion. causes weakness, abnormal heart rhythms, renal failure, coma and death

55

Where are the adrenal glands found?

on top of the kidneys

56

What are the two regions of the adrenal glands?

1. adrenal medulla: outer, glandular region with three layers

2. adrenal cortex: inner, neural tissue region

57

The adrenal medulla functions under what division of the nervous system?

symphatetic nervous system

58

What are the hormones of the adrenal medulla?

1. epinephrine (adrenaline)

2. norepinephrine ( noradrenaline)

59

What are glucocorticoids? What are their functions?

Hormones of the adrenal cortex

1. promote normal cell metabolism

2. help resist long-term stresses by increasing glucose levels

3. help control inflammation and pain

** it is released in response to increased blood levels of ACTH**

60

What is the purpose of the hormones of the adrenal medulla?

to cuase a "flight or fight" response

61

What hormone controls the adrenal cortex?

ACTH

62

What are the three layer (hormones) of the adrenal cortex?

1. mineralocorticoids

2. glucocorticoids

3. atrial natriuretic hormone

** provide long-term stress response**

63

Why is angiotensin ll produced?

in response to renin production

64

When is ANH produced?

in response to high blood volume/pressure

** inhibits the secretion of adolsterone

65

Describe the regulation of blood pressure and volume

high BP: heart secretes ANH into blood, kidneys excrete sodium and water in urine, thus causing a drop in BP

low BP: kidneys secrete renin into the blood, angiotension II coonstricts and causes the adrenal cortex to release aldosterone. The kidneys reabsorp sodium and water from kidneys tubules. Blood pressure then rises

66

List two disorders that occur as a result of the malfunctioning of the adrenal cortex

Addison's disease

Cushing's syndrome

67

Addison disease

hyposecretion of adrenal cortex hormones. Acth causes increased melanin production. lack of cortisol means that glucose cannot be replenished under stress conditions. lack of adolsterone results in the development of low blood pressure and possibly severe dehydration

** a mild infection can be lethal**

68

Cushing's Syndrome

caused by hypersecretion of adrenal cortex hormoes. excess cortisol may lead to diabetes mellitus. excess aldosterone leads to hypertension. edema causes a puffy "moon-shaped" face. increased male sex hormones may cause masculinity in females

69

What is the Endocrine function of the pancreas?

to maintain blood glucose homeostasis

70

What is the function of pancreatic islets?

to produce hormones scattered among enzyme-producing exocrine tissues

71

What does beta cells of islets do?

1. increase the ability to transport glucose across the plasma membrane

2. speeds up oxidation of glucose for energy or conversion to glycogen or fat for storage

72

What does alpha cells of islets do?

They are antagonistic to insulin. They stimulate the liver to break down glycogen to glucose

73

Describe the regulation of blood glucose levels

after eating the pancreas secretes insulin into the blood, liver stores glucose from blood as glycogen, muscle cells stores glycogen and build protein, adipose tissue uses glucose from blood to form fat, glucose levels drop

74

When is glucagon released?

during hypoglycemia

75

What are the three endocrine tissue cell types?

1. glucagon: secreted by alpha cells

2. insulin: secreted by beta cells

3. somatostatin: secreted by delta cells ** prevents release of insulin and glucagon. prevents large swings of blood glucose levels**

76

What are the s/s of diabetes mellitus?

hyperglycemia

polyphagia

glycosuria

poyuria

polyipsia

ketonuria

77

What are the two forms of diabetes mellitus?

Type I (IDDM)

Type II (NIDDM)

78

Type l Diabetes (IDDM)

insulin-dependent diabetes mellitus --> pancreas does not produce insulin. immune cells have destroyed the pancreatic islets due to an autoimmune response. individuals require daily injections of insulin

79

Type ll Diabetes (NIDDM)

non-insulin dependent diabetes mellitus --> more common than type I. tends to occur in obese individuals. normal or elevated amounts of insulin are present in the blood, but the receptors on the cells do not respond to the insulin

tx: exercise and maintaining normal body weight helps control it

80

What are the long term complications of diabetes mellitus?

blindness, kidney disease, heart attack, stroke, gangrene --> amputations

81

Where are the gonads located?

male: in the testes

female: ovaries

82

What are androgens responsible for?

development of sex organs and characteristics --> continuous production of sperm

83

What stimulates the production of androgens?

anterior pituitary gonadotropic hormones

--> increased testosterone, some form of baldness, acne, body odor, facial, axillary and pubic hair, enlargement of larynx and vocal cords

84

What groups of hormones do the ovaries produce?

estrogen and progesterone

--> both necessary for breast development and regulation of uterine cycle

--> estrogen is needed for egg maturation, fat distribution, wider pelvic girdle, growth of uterus

85

What stimulates the production of estrogen and progesterone?

anterior pituitary gonadotropic hormones

86

Where is the thymus gland located?

posterior to the sternum

87

What happens to the thymus gland as we enter adulthood?

it decreases in size

88

What does the thymus gland produce?

thymosin

89

What is the function of thymosin?

To help T lymphocytes mature --> this is important in developing the immune system

90

Where is the pineal gland?

hanging from the roof of the third ventricle in the brain

91

What does the pineal gland secrete?

melatonin

** melatonin help the body's wake and sleep cycles. It peaks at night which causes sleepiness

92

Erythropoietin

production of red blood cells produced by the kidneys

93

Leptin

produced by adipose tissue. signals satiety in the hypothalamus

94

Ghrelin

produced by the stomach. antagonist to leptin, signaling hunger

95

List and describe several types of growth factors

granulocyte and macrophage colony stimulating factor - stimulates bone marrow stem cells

platelet - derived growth factor - wound healing

epidermal growth factor and nerve growth factor - wound healing

tumor angiogenesis factor - formation of capillary networks; released by tumor cells

96

What are some of the effects of prostaglandins?

uterine contractions

mediate the effects of pyrogens (fever inducers)

reduce gastric secretions

lowers blood pressure

inhibit platelet aggregation (blood clot formation)

97

How do cells and organs communicate?

by using chemical signals --> hormones, prostaglandins, nerotransmitters, growth factors

98

Chemical signals between individuals are known as what?

phreomones

99

List some of the effects the aging has on the Endocrine system

thyroid disorders (myexedema, Graves disease)

thymus and pineal glands decreases in size

diabetes mellitus

100

The Endocrine works synonymous with what other system?

nervous system

101

Aside from its own vital functions, what other functions does the Endocrine system help regulate?

digestion

glucose metabolism

blood pressure and volume

calcium balance

response to external environment ( "fight or flight")

102

Mineralocorticoids

regulate salt and water balance for blood volume and pressure

103

Glucocorticoids

regulate carbohydrate, protein and fat metabolism to increase blood glucose levels. secreted in small amounts in both sexes.promotes skeletal growth, changes at puberty, libido

104

Glucagon

secreted when blood levels are low ( between meals)

** antagonistic to insulin