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EPCC Anatomy and Physiology 1 > Chapter 16 Highlights > Flashcards

Chapter 16 Highlights Flashcards

1
Q

How do hormones send their signals?

A
  • Secretes into blood to affect distant targets

- AKA classic endocrine signals

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2
Q

Paracrine

A
  • Chemicals secreted by cells into extracellular space

- Affects nearby but different types of cells

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3
Q

Autocrine signals

A
  • Chemicals secreted by cells into interstitial fluid

- Elicits effects from same cell or cell type

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4
Q

Main groups of hormones

A
  • Amino acid derivatives
  • Peptide hormones
  • Lipid derivatives
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5
Q

Amino acid derivatives

A

Small molecules structurally related to individual amino acids

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6
Q

Peptide hormones

A

Chains of amino acids

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7
Q

Lipid derivatives

A

Molecules structurally related to lipids

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8
Q

Where do single amino acid or polypeptide hormones stay?

A

Outside the cell

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9
Q

What do single amino acid or polypeptide hormones need to activate enzymes inside the cell?

A
  • G proteins

- Second messengers

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10
Q

Classification of hormones

A
  • Amino-acid hormones

- Steroid hormones

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11
Q

Amino-acid hormones

A
  • 1 amino acid = amine hormones
  • Multiple amino acids = peptide hormones
  • Complete proteins = protein hormones
  • Generally considered hydrophilic
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12
Q

What do hydrophilic hormones bind to?

A

Bind to plasma membrane receptors

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13
Q

Steroid hormones

A
  • Developed from cholesterol

- Hydrophobic hormones

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14
Q

Hydrophobic hormones

A
  • Can cross the plasma membrane
  • Binds to receptors in cytosol or nucleus
  • Forms a complex with its receptor
  • Generally interacts with DNA of target cell
  • Effects by changing rate of protein synthesis
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15
Q

Pituitary gland

A
  • Small organ

- Sits in sella turcica of sphenoid

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16
Q

2 structurally and functionally distinct components of pituitary gland

A
  • Anterior pituitary

- Posterior pituitary

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17
Q

Anterior pituitary

A
  • Adenohypophysis
  • True gland
  • Hormone-secreting glandular epithelium
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18
Q

Posterior pituitary

A
  • Neurohypophysis

- Nervous tissue

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19
Q

Hypothalamic-hypophyseal portal system

A
  • Specialized blood supply

- Allows both hypothalamus and pituitary to deliver hormones directly to target cells

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20
Q

What kind of blood vessels merge in hypothalamus

A
  • Tiny capillaries

- They eventually form larger portal veins that travel through infundibulum

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21
Q

Where to the portal veins lead?

A

To a second group of capillaries in anterior pituitary gland

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22
Q

Portal system

A

A system in which capillaries are drained by veins that lead to another set of capillaries

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23
Q

Are any hormones made in posterior pituitary?

A
  • No

- 2 neurohormones are produced by hypothalamus and then stored and released from posterior pituitary

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24
Q

Neurohormones produced by hypothalamus and stored in posterior pituitary

A
  • Antidiuretic hormone (ADH)

- Oxytocin

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25
Q

Function and production of antidiuretic hormone (ADH)

A
  • Controls water balance

- Produced continually in low amounts by hypothalamus neurons

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26
Q

How is ADH transported?

A
  • Through axons in infundibulum to axon terminals in posterior pituitary
  • Then stored in synaptic vesicles
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27
Q

Do the axon terminals in posterior pituitary have synapses?

A
  • Do not have synapses

- Instead releases ADH into blood vessels when stimulated by action potentials

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28
Q

Aquaporins

A

ADH allows for insertion of water channels called aquaporins into plasma membranes of kidney tubule cells

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29
Q

What happens to the water in aquaporins?

A
  • Water first passes into cytosol of cells
  • Proceeds back into the extracellular fluid
  • Moves into the blood, otherwise would have been eliminated from body in urine
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30
Q

Diabetes insipidus

A
  • Caused by lack of ADH secretion or activity
  • Causes extreme thirst and signs of dehydration
  • Body is unable to conserve most water consumed
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31
Q

Oxytocin

A
  • Produced by hypothalamus

- Stored in axon terminals of posterior pituitary gland

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32
Q

Function of oxytocin

A
  • Primary focused on reproduction

- Target cells are in mammary glands of breast tissue and smooth muscle of uterus

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33
Q

What stimulates oxytocin release in nursing mothers?

A
  • Suckling

- Causes mammary glands to contract, resulting in milk ejection

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34
Q

Milk let-down reflex

A
  • Positive feedback loop
  • Suckling induces lactation, causing more suckling and more milk to be released
  • Loop ceases when satisfied infant stops suckling
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35
Q

How does the hypothalamus control the anterior pituitary?

A
  • Hypothalamus produces and releases tropic hormones

- Either stimulates or inhibits release of hormones

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36
Q

Transport of tropic hormones

A

Travels via the hypothalamic-hypophyseal portal system

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37
Q

What kind of hormones are many anterior pituitary hormones?

A
  • Tropic

- Control secretion of hormones by various endocrine glands in body

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38
Q

First tier hypothalamic control

A

Neuroendocrine cells of hypothalamus secrete releasing and inhibiting hormones in response to change in homeostatic variable (tropic hormones)

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39
Q

Second tier hypothalamic control

A
  • Tropic hormones’ effect on anterior pituitary

- Stimulates or inhibits anterior pituitary hormone secretion

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40
Q

Third tier hypothalamic control

A
  • Actions of anterior pituitary hormones at target tissues

- Target tissue glands secrete hormones that can affect various homeostatic variables

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41
Q

Divisions of the anterior lobe

A
  • Pars distalis
  • Pars intermedia
  • Pars tuberalis
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42
Q

Pars distalis

A
  • Secretes 6 hormones, 4 are tropins
  • Growth hormone (GH)
  • Thyroid-stimulating hormone (TSH) tropic
  • Adrenocorticotropic hormone (ACTH) tropic
  • Follicle-stimulating hormone (FSH) tropic
  • Luteinizing hormone (LH) tropic
  • Prolactin (PRL)
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43
Q

Pars intermedia

A

Secretes 1 hormones (MSH)

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44
Q

Anterior pituitary hormones that affect other glands

A
  • Luteinizing hormone
  • Follicle-stimulating hormone
  • Prolactin
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45
Q

Luteinizing hormone effect on men

A

Stimulates production of testosterone by testes under direction of hypothalamic gonadotropin-releasing hormone (GnRH)

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46
Q

Luteinizing hormone effect on women

A
  • Stimulates production of estrogen and progesterone from ovaries
  • Triggers release of oocyte in ovulation
  • Also under direction of GnRH
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47
Q

Follicle-stimulating hormone effect on men

A
  • Stimulates cells of testes to produce chemicals that bind and concentrate testosterone
  • Under direction of GnRH
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48
Q

Follicle-stimulating hormone effect on women

A
  • FSH and LH together trigger production of estrogen

- FSH also triggers maturation of ovarian follicles (house developing oocytes)

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49
Q

Prolactin

A
  • Stimulates growth of mammary gland tissue
  • Initiates milk production after childbirth
  • Maintains milk production during breastfeeding
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50
Q

What stimulates release of prolactin?

A
  • Release stimulated by hypothalamic prolactin-releasing hormone
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51
Q

What inhibits release of prolactin?

A
  • Release inhibited by prolactin-inhibiting factor (dopamine)
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52
Q

What is the effect of growth hormone?

A

Stimulates cell growth and replication through release of somatomedins or IGF (insulinlike Growth Factors)

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53
Q

What stimulates the release of growth hormone?

A

Hypothalamus –> Growth-hormone releasing hormone (GH-RH)

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54
Q

What inhibits the release of growth hormone?

A

Hypothalamus –> Growth-hormone inhibiting hormone (GH-IH)

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55
Q

What cells are most sensitive to growth hormone?

A

Skeletal muscle and cartilage cells

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56
Q

What role does the liver play with growth hormone?

A
  • Liver stimulates IGF

- IGF binds to cells and increases rate of amino acid production to make proteins

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57
Q

Effects of growth hormone?

A
  • Breakdown of fat

- Breakdown of stored glycogen in liver

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58
Q

What happens when growth hormone stimulates the breakdown of fat?

A
  • Fats breakdown
  • Fatty acids increase in blood
  • Greater use by tissues
  • Decreased glucose consumption leads to a glucose-sparing effect
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59
Q

What happens when growth hormone stimulates the breakdown of glycogen?

A
  • Glycogen breakdown
  • Increased glucose in the blood
  • Increased glucose can have diabetogenic effect (can lead to an endocrine disorder)
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60
Q

Hypothalamic hormones which regulate growth hormone

A
  • Growth hormone-releaseing hormone

- Hypothalamic somatostatin

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61
Q

When does growth hormone-releasing hormone secretion increase?

A

During exercise, fasting, stress, and after ingestion of protein-rich meal

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62
Q

Growth hormone disorders

A
  • Giantism
  • Acromegaly
  • Pituitary dwarfism
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63
Q

Giantism

A
  • Hypersecretion of GH BEFORE epiphyseal plate closure
  • Leads to extremely tall people
  • Also increases size of other tissues (heart)
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64
Q

Acromegaly

A
  • Hypersecretion of GH AFTER epiphyseal plate closure
  • Progressively distorts organs
  • Can lead to heart failure
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65
Q

What body parts are most affected by acromegaly?

A

Tissues of head, face, hands, feet, liver, and heart

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66
Q

Pituitary dwarfism

A
  • Hyposecretion of GH

- Leads to short, but proportional, individuals

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67
Q

What does the thyroid gland secrete?

A
  • Thyroid hormone

- Calcitonin

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68
Q

Parafollicular (C) cells

A
  • Neuroendocrine cells in the thyroid

- Secrete calcitonin

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69
Q

What does calcitonin do?

A
  • Reacts to calcium concentration in the blood
  • Acts to decrease calcium concentration
  • Decreases osteoclast activity
  • Lengthens life span of osteoblasts
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70
Q

What is the microscopic composition of the thyroid and parathyroid glands?

A
  • Thyroid follicles (multiple spheres)

- Follicle cells at outer edge of follicles produce and secrete thyroid hormones

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71
Q

Colloid

A

Protein-rich, gelatinous material

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72
Q

What do colloids contain?

A
  • Precursor for thyroid hormone and a high concentration of iodine atoms
  • Both are important to thyroid hormone synthesis
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73
Q

Parafollicular cells

A
  • In spaces between adjacent thyroid follicles

- Large cells that produce calcitonin

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74
Q

Parathyroid glands

A
  • Typically 3-5 separate glands

- On posterior surface of thyroid gland

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75
Q

What do parathyroid glands secrete?

A

Parathyroid hormone from chief cells

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76
Q

Chemical structure of thyroid hormone

A

Amino acid core bound to either 3 or 4 iodine atoms

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77
Q

Amino acid core bound to 3 iodine atoms

A
  • Triiodothyroxine

- T3

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78
Q

Amino acid core bound to 4 iodine atoms

A
  • Thyroxine

- T4

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79
Q

Enzyme responsible for making T3 and T4

A

Thyroid peroxidase

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80
Q

Thyroglobulin

A
  • Large thyroid hormone precursor protein

- Secrete by follicle cells into colloid

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81
Q

Relationship between iodine and TSH

A

TSH stimulates iodine to be pumped (ion pump) into the follicle cell

82
Q

Where are iodide ions secreted into?

A

Colloid

83
Q

What are iodide ions converted into?

A

Iodine atoms that attach to thyroglobulin by thyroid peroxidase

84
Q

Thyroid follicles

A

-

85
Q

First tier of T3 and T4 control

A

Thyrotropin-releasing hormone (TRH) is released from hypothalamus

86
Q

Second tier of T3 and T4 control

A

Thyroid stimulating hormone (TSH) is released from anterior pituitary gland

87
Q

What does thyroid-stimulating hormone do?

A
  • Stimulates iodine to be pumped into the follicle cell
88
Q

After stimulating iodine to be pumped, what does thyroid peroxidase do?

A

It produces T3 and T4 and attaches to thyroglobulin

89
Q

Third tier of T3 and T4 control

A

Release of T3 and T4

90
Q

What inhibits secretion of TRH and TSH?

A
  • Rising levels of free T3 and T4

- Somatostatin

91
Q

Common thyroid disorders

A
  • Hyperthyroidism

- Hypothyroidism

92
Q

Symptoms of hyperthyroidism

A
  • Weight loss
  • Heat intolerance
  • Disruptions in blood pressure and heart rhythm
  • Development of goiter and exophthalmos
93
Q

Goiter

A

Enlargement of thyroid gland

94
Q

Exophthalmos

A

Protruding eyeballs

95
Q

Graves’ disease

A
  • Most common hyperthyroidism

- Immune system produces abnormal proteins that mimic actions of TSH on thyroid gland

96
Q

Symptoms of hypothyroidism

A
  • Weight gain
  • Cold intolerance
  • Slow heart rate
  • Low BP
  • Goiter
97
Q

Possible reasons for hypothyroidism

A
  • Immune system disorder

- Lack of available iodine

98
Q

Congenital hypothyroidism

A
  • Cretinism

- Develops when infant is born with inadequate thyroid function

99
Q

What happens when cretinism is present?

A
  • Can lead to physical and nervous system development delays

- Can lead to potential mental retardation if left untreated

100
Q

What cells secrete parathyroid hormone (PTH)?

A

Chief cells

101
Q

What does parathyroid hormone affect?

A

Maintenance of blood calcium ion concentration

102
Q

What is parathyroid hormone secreted in response to?

A

Declining calcium ion levels in blood

103
Q

What are the effects of parathyroid hormone?

A
  • Increases release of calcium ions from bone by stimulating osteoclast activity
  • Increases absorption of dietary calcium ions by small intestine
104
Q

Where are the adrenal glands located?

A

Superior aspect of each kidney

105
Q

Describe the shape of the adrenal glands

A

Roughly pyramid-shaped

106
Q

What do the adrenal glands produce?

A
  • Catecholamine

- Steroid hormone

107
Q

Regions of adrenal glands

A
  • Cortex

- Medulla

108
Q

Cortex of adrenal gland

A
  • Outer region

- Typical endocrine gland with functions similar to what has already been discussed

109
Q

Medulla of adrenal gland

A
  • Inner region

- Neuroendocrine organ that secretes neurohormones

110
Q

Hormones secrete by the adrenal cortex

A
  • Aldosterone
  • Cortisol
  • Androgens
111
Q

Cells that secrete aldosterone

A

Densely packed cells

112
Q

Cells that secrete cortisol and androgens

A

Cells stacked on one another in columns

113
Q

Cells that secrete epinephrine and norepinephrine

A

Thin layer of cells arranged loosely in clusters

114
Q

Zones of the adrenal cortex

A
  • Zona glomerulosa
  • Zona fasciculata
  • Zona reticularis
115
Q

Hypothalamic-pituitary-adrenocortical (HPA) axis

A

Multi-tiered negative feedback loop which partially regulates the adrenal cortex

116
Q

Functions of aldosterone

A
  • Regulates concentration of sodium and potassium ions in the body
  • Regulates extracellular fluid volume
  • Maintains BP
  • Maintains acid-base homeostasis
117
Q

How does aldosterone regulate concentration of sodium and potassium ions in the body?

A

Ion gradients are important for function of muscle cells and neurons

118
Q

How does aldosterone regulate extracellular fluid volume?

A
  • Creates concentration gradient

- Favors movement of water from fluid in the tubules to extracellular fluid and blood

119
Q

How does aldosterone maintain BP?

A
  • Maintains blood pressure through complex series of interactions called renin-angiotensin-aldosterone system (RAAS)
  • Increases BP
  • Preserves blood flow to hear, brain, and kidneys
120
Q

How does aldosterone maintain acid-base homeostasis?

A
  • Activates hydrogen ion pumps in cells of kidney tubules

- Pumps transport hydrogen ions from extracellular fluid into fluid of tubules

121
Q

What happens to the hydrogen ions after they are pumped into the kidney tubules?

A
  • Excreted in urine
  • This lowers pH of blood
  • Preserves slightly alkaline pH
122
Q

Aldosterone disorders

A

Hyperaldosteronism

123
Q

What disorders can hyperaldosteronism lead to?

A
  • Hypokalemia
  • Hypernatrmia
  • Hypertension
124
Q

Hypokalemia

A

Low blood potassium ion level

125
Q

Hypernatrmia

A

High blood sodium ion level

126
Q

Hypertension

A

High blood pressure

127
Q

Glucocorticoids

A

Produced in zone fasciculata and zona reticularis

128
Q

What is the role of glucocorticoids?

A

Mediate body’s response to stress

129
Q

Cortisol

A
  • Hydrocortisone

- Most potent glucocorticoid

130
Q

Stress response

A

Events that maintain homeostasis when the body is faced with a stressor

131
Q

What role does cortisol play in the stress response

A

Regulates of blood glucose levels by cortisol

132
Q

What happens when cortisol stimulates liver cells?

A
  • Synthesizes enzymes of gluconeogenesis

- Increases blood glucose levels

133
Q

Effects of the stress response

A
  • Proteins breakdown –> amino acids can be converted to glucose
  • Adipocytes release fatty acids –> converted into ATP or glucose in liver
  • Decreases levels of certain leukocytes –> anti-inflammatory agent
134
Q

First tier of cortisol regulation

A
  • CRH secreted daily from hypothalamus in rhythmic fashion

- Peak CRH levels generally in morning

135
Q

Second tier of cortisol regulation

A

CRH stimulates ACTH release from anterior pituitary

136
Q

Third tier of cortisol regulation

A

ACTH stimulates cortisol production and secretion from adrenal cortex

137
Q

Elevated cortisol levels suppress the release of what?

A
  • Corticotropin-releasing hormone (CRH)

- Adrenocorticotropic hormone (ACTH)

138
Q

What does elevated cortisol levels do to the HPA axis?

A

Closes the negative feedback loop

139
Q

Cushing’s disease

A
  • Oversecretion from adrenal cortex, usually from tumor
  • Can result in moon facies (round face)
  • Back of neck producing “buffalo hump”
140
Q

Latrogenic Cushing’s syndrome

A

Disorder caused by long-term administration of glucocorticoid-containing products

141
Q

Addison’s disease

A
  • Hyposecretion from adrenal cortex
  • Results in decreased glucose and Na+ levels
  • Weight loss, severe dehydration, and hypotension
142
Q

Androgenic steroids

A
  • Steroid sex hormones that affect reproductive organs as well as other tissues
  • Can be converted in circulation to androgen testosterone or female hormone estrogen
143
Q

Hormones of the adrenal medulla

A
  • Epinephrine (catecholamine)

- Norepinephrine

144
Q

What are chromaffin cells derived from?

A

Nervous tissue

145
Q

What do chromaffin cells secrete?

A

Epinephrine (catecholamine)

146
Q

What kind of responses do chromaffin cells elicit?

A

They mediate immediate responses to stressor

147
Q

What effects do chromaffin cells have?

A
  • Increase rate and force of heart contraction
  • Dilate bronchioles in lung
  • Constrict blood vessels supplying skin, digestive organs, and urinary organs
  • Dilate blood vessels supplying skeletal muscles
  • Dilate pupils
  • Decrease digestive and urinary functions
148
Q

Cell types in pancreas

A
  • Alpha cells
  • Beta cells
  • Delta cells
149
Q

Pancreatic islets

A
  • Islets of Langerhans
  • Small rounded islands populated by endocrine cells
  • Secrete hormones into the bloodstream
150
Q

What cells secrete glucagon?

A

Alpha cells

151
Q

What are the major target tissues of glucagon?

A
  • Liver cells
  • Muscle tissue
  • Adipose tissue
152
Q

What kind of reactions does glucagon promote?

A

Reactions that increase levels of glucose and metabolic fuels in blood

153
Q

Insulin is the antagonist of what hormone?

A

Glucagon

154
Q

Where is insulin produced?

A

Beta cells of pancreatic islets

155
Q

What responses does insulin stimulate in target cells?

A
  • Uptake and storage of ingested nutrients
  • Lowers blood glucose levels
  • Synthesis of glycogen in liver
  • Synthesis of fat from lipids and carbs
  • Promotes satiety (feeling of fullness)
156
Q

What causes type I diabetes?

A

Destruction of beta islet cells

157
Q

What is the mechanism of type I diabetes?

A
  • Target cells are unable to take in circulating glucose
  • Glucose is overproduced in liver because of unopposed actions of glucagon
  • Glucagon also elevates level of ketone bodies in blood
158
Q

What are the effects of type I diabetes?

A
  • Glucose and ketones in urine
  • Draws water from ECF by osmosis
  • Causes polyuria and polydipsia
159
Q

Polyuria

A

Frequeny urination

160
Q

Polydipsia

A

Excessive thirst

161
Q

What causes type II diabetes?

A
  • Insulin’s target tissues become insensitive to insulin

- Target cells do not respond properly to blood glucose concentration

162
Q

What are the results of type II diabetes?

A

Hyperglycemia

163
Q

Signs and symptoms of hyperglycemia

A
  • Glucosuria
  • Polyurai
  • Polydipsia
164
Q

Glucosuria

A

Glucose in the urine

165
Q

Pineal gland

A

Primary endocrine component of epithalamus (posterior region of diencephalon of brain)

166
Q

What effect does melatonin have?

A
  • It is related to light and dark cycles
  • Secretion increases in the dark
  • Appears to adjust sleep/wake cycle in some individuals
  • Inhibits GnRH secretion from hypothalamus
167
Q

What tissues does melatonin target?

A

Sleep-regulation centers

168
Q

Where are the sleep-regulation centers located?

A

Reticular formation of brainstem

169
Q

Thymus

A
  • Primary endocrine gland in mediastinum

- Located where T lymphocytes mature

170
Q

What hormones does the thymus secrete?

A
  • Thymosin

- Thymopoietin

171
Q

What is the function of thymosin and thymopoietin?

A

Paracrine signals that assist in T lymphocyte maturation

172
Q

Primary male and female reproductive organs

A
  • Testes (male)

- Ovaries (female)

173
Q

Target tissues of testosterone

A
  • Male reproductive organs

- Multiple other target tissues

174
Q

Effects of testosterone

A
  • Androgenic effects

- Anabolic effects

175
Q

Target tissues of estrogen

A

Female reproductive organs

176
Q

Effects of estrogen

A
  • Development of female secondary sex characteristics
  • Regulation of menstrual cycle
  • Multiple other effects
177
Q

Target tissues of progesterone

A

Multiple other target tissues

178
Q

Effects of progesterone

A
  • Prepares the body for pregnancy
  • Support fetal development
  • Multiple other effects
179
Q

Where do males produce a small amount of estrogen?

A

In adrenal glands

180
Q

When does progesterone secretion peak?

A

After ovulation and during pregnancy

181
Q

What hormones does adipose tissue produce?

A
  • Leptin
  • Resistin
  • Adiponectin
182
Q

Leptin

A
  • Appetite control
  • Prevents overfeeding
  • Stimulates increased energy expenditure
183
Q

Can leptin cross the blood-brain barrier

A

Yes

184
Q

What neurons does leptin interact with?

A

Hypothalamic neurons

185
Q

Resistin

A

Insulin antagonist

186
Q

Adiponectin

A

Enhances sensitivity to insulin

187
Q

Where are enteroendocrine cells located?

A

Gastrointestinal tract

188
Q

What hormones do enteroendocrine cells produce?

A
  • Gastrin
  • Secretin
  • Cholecystokinin
  • Serotonin
189
Q

Function of Gastrin

A

Stimulates release of HCl

190
Q

Function of Secretin

A

Stimulates liver and pancreas

191
Q

Function of Cholecystokinin

A

Stimulates pancreas, gallbladder, and hepatopancreatic sphincter

192
Q

Function of Serotonin

A

Acts as paracrine

193
Q

Osteocalcin

A
  • Prods pancreas to secrete more insulin
  • Restricts fat storage
  • Improves glucose handling
  • Reduces body fat
194
Q

What activates osteocalcin?

A

Insulin

195
Q

Are osteocalcin levels high or low in type II diabetes

A
  • Low

- Increasing levels may be new treatment

196
Q

Cholecalciferol

A

Precursor of vitamin D

197
Q

What causes atrial natriuretic peptide (ANP) secretion?

A

When increased blood volume stretches stretch-sensitive ion channels

198
Q

What is the effect of atrial natriuretic peptide?

A
  • Relaxation of smooth muscle cells in blood vessels (vasodilation)
  • Natriuresis
  • Enhances water excretion from kidneys
199
Q

Natriuresis

A
  • Enhancing excretion of sodium ions from kidneys

- Creates concentration gradient that water follows into kidney fluid by osmosis

200
Q

What effect does vasodilation and natriuresis have?

A
  • Decrease blood volume

- Lower BP

201
Q

What hormones do the kidneys secrete?

A
  • Erythropoietin (EPO)

- Renin

202
Q

Renin

A
  • Converts plasma protein angiotensinogen to angiotensin I

- Maintains blood pressure

EPCC Anatomy and Physiology 1 (24 decks)

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