Topic 11: Endocrine System:

1
Topic 11 Endocrine System
BIOL 220 Anatomy Physiology I

• Chapter 16
• pp. 603-643

J. Ellen Lathrop-Davis Assistant Professor
Interactive Physiology Endocrine System
2
Overview

• Major control system
• Diverse locations, actions
• Endocrine tissues
• Dedicated glands
• Tissues within organs with other major functions
  (AP II)
• Chemical messengers (ligands)
• Hormones
• Carried through body fluids (plasma)

3
Comparison with Nervous System
N
Nervous system Endocrine System
Organization hardwired (receptors, neurons, effectors physically connected) Loose organization of diffuse tissues may be far apart connected by body fluids
Communica-tion Electrical (gap juctions) chemical (NTs) Chemical (hormones)
4
Comparison with Nervous System
Nervous system Endocrine System
Speed Rapid (fractions of a second) Slower (minutes to hours or days)
Duration Short (only as long as impulses are generated) Prolonged (minutes to days)
Responses Based on gap junctions or receptors in plasma membrane Based on receptors in plasma membrane or intracellular receptors
5
Endocrine Organs Tissues
Exclusively Endocrine Major Endocrine With Other Major Functions Minor Endocrine (AP II)
Pituitary Thyroid Parathyroid Adrenal Pineal Pancreas Gonads (testes, ovaries) Hypothalamus Thymus Adipose Stomach Small intestine Kidneys Heart
Fig. 16.1, p. 604
6
Hormones
N

• Alter activity within target cells
• Carried to all cells only cells with receptors
  are target cells
• Act through receptors in target cells
• Plasma membrane receptors
• Intracellular receptors

7
Hormone Types and Mechanisms

• Types
• Amino-acid based hormones
• Steroid hormones
• Eicosanoids
• Mechanisms of Action (MOAs)
• Second messenger systems
• Gene activation

8
Hormone Types Amino Acid-Based Hormones
N

• Modified amino acids (e.g., thyroxine,
  norepinephrine, epinephrine), short peptides
  (e.g., oxytocin), proteins (e.g., insulin)
• Almost all hormones except products of adrenal
  cortex and major products of gonads
• Water soluble
• Interact with plasma membrane receptors generate
  second messengers

9
Hormone Types Steroids
N

• Synthesized from cholesterol
• Major products of gonads all products of adrenal
  cortex
• Lipid soluble
• Transported by carrier proteins in the blood (AP
  II)
• Enter cells to affect gene activity

10
Hormone Types Eicosanoids
N

• Synthesized from arachidonic acid
• Act locally
• Lipid soluble
• Important to inflammation, pain (AP II)
• prostaglandins

11
MOA Second Messenger Systems

• Used by amino acid-based hormones
• Involves interaction between hormone and plasma
  membrane receptor
• Alter activity of proteins (activate/ inactivate)
  already present in cell
• Hormone is 1st messenger

12
Second-Messenger Systems
N

• Hormone interacts with plasma membrane receptor,
  activates plasma membrane protein
• G protein activates adenylate cyclase or
  phospholipase C
• Intracellular second messengers
• adenylate cyclase cAMP
• phospholipase C DAG, IP3, Ca2
• 2nd messenger causes effects in cell including
  phosphorylation by kinase enzymes

http//student.ccbcmd.edu/c_anatomy/animations/cAM
P/cAMP.htm
Fig. 16.2, p. 606-607
13
MOA Altered Gene Activity

• Used by steroid and thyroid hormones
• Lipid soluble hormones diffuse through plasma
  membrane
• Hormone interacts with intracellular receptor ?
  Hormone-receptor complex interacts with DNA ?
  Increases RNA synthesis ? Protein synthesis
  increases

http//www.people.virginia.edu/rjh9u/genereg.html
Fig. 16.3, p. 608
14
Types of Hormone Effects

• Altered membrane ion permeability
• Increased or decreased activity of intracellular
  proteins (enzymes)
• Secretion
• Increased intracellular activity including DNA
  transcription
• Increased synthesis of specific proteins within
  cell
• Cell division

15
Overall Response
N

• Depends on
• Amount of circulating hormone
• Rate of release
• Half-life time for ½ of hormone to be removed
  (affected by liver and kidney activity)
• Affinity of receptor for hormone
• Number of receptors (dynamic membrane)

16
Number of Receptors
N

• Down regulation decreased number of receptors
• Up regulation increased number of receptors
• Cross regulation one hormone influences the
  number of receptors for another hormone (e.g.,
  progesterone/ estrogen)

17
Other Terms

• Onset time from release to effect
• Duration how long effects last
• Kidney or liver disorders affect duration

18
Hormone Interactions
N

• Permissive effects 2nd needed for 1st to act
• Synergistic effects effects of both are greater
  than sum of individual effects
• Antagonistic effects effects of 2nd decrease
  effects of 1st

19
Control of Hormone Release
Hormonal
Neural
Humoral
On the endocrine study sheet, indicate how each
hormone is controlled.
Fig. 16.4, p. 611
20
Endocrine Pathologies

• Symptoms depend on action of hormone
• Damage to gland - Primary pathology
• e.g., primary hypothyroidism
• Tumor (often increases secretion)
• Cell death (decreases secretion)
• Damage to control mechanism Secondary pathology
  
• e.g., anterior pituitary tumor leading to
  increased thyroxine release

21
Endocrine Pathologies

• Damage to receptors
• e.g., type II diabetes mellitus
• Secretion of controlling hormone due to pathology
  of another organ/tissue
• e.g., secretion of ACTH by some lung tumors

22
Pathologies Amount of Secretion

• Hyposecretion
• Abnormally low amount of hormone secreted
  resulting in decreased activity
• e.g., hypothyroidism leads to abnormally low body
  temperature
• Hypersecretion
• Abnormally high amount of hormone exaggerates
  normal activity
• e.g., hyperthyroidism leads to abnormally high
  body temperature

23
Think-Pair-Share Pathologies
Identify the following as primary or secondary hypo- or hypersecretion Identify the following as primary or secondary hypo- or hypersecretion
Increased thyroxine due to pituitary tumor
Decreased insulin due to pancreatic damage
Decreased cortisol due to pituitary removal
Increased cortisol due to adrenal tumor
24
Major Endocrine Glands

• Pituitary gland
• Adenohypophysis
• Neurohypophysis
• Thyroid gland
• Parathyroid glands
• Pancreas
• Gonads (ovaries / testes)
• Adrenal glands

Fig. 16.1, p. 604
25
Overview
Endocrine System Review, pp. 3-4

• For each organ you should be able to
• Describe the location and structure of the gland
• List the major hormones
• Classify and describe the control
• Indicate how each interacts with its target cells
• Indicate the major target tissue(s) and the
  effect(s) on each tissue (actions)
• Describe the major disorders
• Apply the terms primary and secondary, hypo- and
  hypersecretion to selected disorders

26
Pituitary Gland

• Two regions of different embryonic origin
• Adenohypophysis
• Grows up from roof of mouth
• Neurophypophysis
• Grows down from hypothalamus

http//calloso.med.mun.ca/tscott/head/pit.htm
27
Pituitary Gland

• Adenohypophysis
• Modified epithelial cells
• Hypophyseal portal system links adenohypophysis
  to hypothalamus
• Neurophypophysis
• Cell bodies of neurosecretory cells in
  hypothalamic nuclei
• Axon terminals in neurohypophysis release
  oxytocin (OT) or antidiuretic hormone (ADH)

Fig. 16.5, p. 612
http//www.usc.edu/hsc/dental/ghisto/end/c_1.html
28
Adenohypophysis

• Secretes short peptides or proteins
• Think Spot How do they interact with cells?
• Secretion controlled by releasing (and
  inhibiting) hormones from hypothalamus
• Think Spot What type of control is this?

29
Adenohypophysis Hormones

• 4 tropic hormones
• TSH thyroid stimulating hormone
• FSH follicle stimulating hormone
• LH luteinizing hormone
• ACTH adrenocorticotrophic hormone
• 2 act on body cells other than endocrine glands
• GH growth hormone
• PRL prolactin

30
Adenohypophysis TSH

• Control
• Stimulus thyroid-releasing hormone (TRH) from
  hypothalamus
• TRH released in response to
• Low circulating thyroxine
• Prolonged cold
• Inhibition increased thyroxine acts on anterior
  pituitary and hypothalamus

31
Adenohypophysis TSH

• Target thyroid gland
• Action increased thyroid hormone (T3, T4)
  secretion
• Disorders
• Secondary hyperthyroidism when too much TSH is
  produced (e.g., tumor)
• Secondary hypothyroidism - when too little TSH
  is produced (e.g., damage or removal of gland)

32
Adenohypophysis FSH

• Control
• Stimulus GnRH from hypothalamus
• Inhibition rising levels of gonadal hormones
• Target ovaries (female) / testes (male)
• Action
• Ovaries - stimulates follicle development,
  estrogen secretion
• Testes stimulates sperm production

33
Adenohypophysis LH

• Control
• Stimulus gonadotropin releasing hormone (GnRH)
  from hypothalamus
• Inhibition rising levels of gonadal hormones
• Target ovaries (female) / testes (male)
• Action increases secretion of gonadal hormones
• Ovaries - estrogen and progesterone
• Testes testosterone

34
Adenohypophysis ACTH
N

• Control
• Stimulus corticotropin-releasing hormone (CRH)
  from hypothalamus
• CRH released in daily rhythm (increases in
  morning)
• Other stimuli for CRH response to stress, fever,
  hypoglycemia
• Inhibition rising levels of cortisol from
  adrenal cortex inhibit release of CRH and act on
  anterior pitiutary

35
Adenohypophysis ACTH

• Target adrenal cortex
• Action increased secretion of cortical
  hormones, especially cortisol
• Disorders
• Secondary hypersecretion of cortisol and
  aldosterone Cushings disease
• Secondary hyposecretion of cortisol

36
Adenohypophysis GH

• Control
• Stimulus growth hormone releasing hormone
  (GHRH) from hypothalamus
• Other stimuli increased estrogen levels,
  hypoglycemia, decreased plasma fatty acids,
  exercise, stress
• Inhibition growth hormone inhibiting hormone
  (GHIH) from hypothalamus (response to increased
  GH, hyperglycemia, lipidemia, obesity)

37
Adenohypophysis GH
N
Targets Actions
Bone, cartilage, skeletal muscle Stimulates protein synthesis leading to growth
Bone, cartilage, skeletal muscle Decreased glucose use (diabetogenic effect)
Adipose Increases fat breakdown and release
Liver Increased glycogenolysis and glucose release
38
Adenohypophysis GH Disorders

• Hypersecretion
• Gigantism before epiphyseal plates close
  excessive height
• Acromegaly increased size of facial features,
  hands, feet may occur after plates close

www.emedicine.com/ ped/topic2634.htm
39
Adenohypophysis GH Disorders

• Hyposecretion
• Dwarfism epiphyseal plates close prematurely
  short stature

http//www.disabledwomen.net/edge/curriculum/biolo
gy.htm
40
Adenohypophysis PRL
N

• Control
• Stimulus prolactin releasing hormone (PRH) from
  hypothalamus (sucking stimulates PRH release)
• Inhibition prolactin inhibiting hormone (PIH)
  from hypothalamus
• Target breasts
• Action stimulates production of milk

41
Think-Pair-Share Anterior Pituitary Hormones
List the major adenohypophyeseal hormone and indicate their major targets and actions List the major adenohypophyeseal hormone and indicate their major targets and actions List the major adenohypophyeseal hormone and indicate their major targets and actions





42
Think-Pair-Share Anterior Pituitary Hormones
List the major adenohypophyeseal hormone and indicate their major targets and actions List the major adenohypophyeseal hormone and indicate their major targets and actions List the major adenohypophyeseal hormone and indicate their major targets and actions




43
Neurohypophysis Hormones

• Secretes short peptides or proteins
• Think Spot How do they interact with cells?
• Secretion controlled by neural impulses from
  hypothalamus
• Think Spot What type of control is this?
• Pituicytes support and protect neurons
• Hormones
• Antidiuretic hormone (ADH)
• Oxytocin (OT)

44
Neurohypophysis ADH
N

• Control
• Stimulus increased plasma osmolarity (solute
  concentration) stimulates osmoreceptors in
  hypothalamus
• Other stimuli decreased blood volume, decreased
  blood pressure, pain, nicotine
• Inhibition increased blood pressure, decreased
  plasma osmolarity, alcohol, some diuretics (AP
  II)

45
Neurohypophysis ADH
N

• Target renal tubules
• Actions
• Increased water reabsorption (decreased water
  output)
• Intense vasoconstriction at high levels
  (important to bodys response to blood loss AP
  II)
• Disorders
• Diabetes insipidus hyposecretion due to damage
  to hypothalamus or pituitary
• Think Spot What are the symptoms?

46
Neurohypophysis OT

• Control
• Stimulus stretching of cervix (uterus),
  suckling on breast (mammary gland) generate
  afferent impulses resulting in impulses from
  hypothalamus
• Positive feedback
• Targets / actions
• Uterus / contraction of smooth muscle
• Mammary gland / release of milk

47
Thyroid Gland

• Located in anterior cervical region
• 2 lobes connected by isthmus
• Two types of cells
• Follicular cells
• Parafollicular cells

http//www.usc.edu/hsc/dental/ghisto/end/c_26.html
Fig. 16.7, p. 619
48
Thyroid Gland

• Follicular cells
• Simple cuboidal cells form thyroid follicles
• Produce thyroglobulin (iodinated protein from
  which thyroxine is made) stored in colloid
• Parafollicular cells
• Protrude into connective tissue around follicle
• Produce calcitonin

http//www.usc.edu/hsc/dental/ghisto/end/c_26.html
49
Thyroid Gland Thyroxine

• Iodinated tyrosine dimers
• T3 more powerful, less abundant
• T4
• Less powerful, more abundant
• Much converted to T3
• Interact with intracellular receptors to alter
  gene activity
• Specifically genes involved in glucose catabolism

50
Thyroid Thyroxine
N

• Control stimulated by TSH (see TSH control)
  inhibited by rising thyroxine
• Target most body cells (except adult brain,
  spleen, testes, uterus, thyroid)
• Main Actions
• Increases synthesis of glucose oxidation enzymes
• Increases metabolism (increased oxygen use and
  heat production PhysioEx)

51
Thyroid Thyroxine

• Other Actions
• Regulates development of reproductive, skeletal
  and nervous systems
• Regulates number of adrenergic receptors on blood
  vessels and heart to maintain normal blood
  pressure (BP)

52
Thyroid Disorders Hyposecretion

• Decreased production of thyroxine
• Results from damage to thyroid (e.g., Hashimotos
  thyroid), pituitary and hypothalamus decreased
  dietary iodine
• In adult myxedema
• Symptoms decreased metabolic rate, feelings of
  being cold, edema (AP II), lethargy, decreased
  mental activity, decreased heart rate (HR) and BP

53
Thyroid Disorders Hyposecretion
N

• Endemic goiter enlargement of thyroid due to
  dietary deficiency
• Adenohypophysis secretes more TSH in attempt to
  produce thyroxine
• Treated with dietary iodine
• Cretinism decrease during infancy resulting in
  retardation and disproportionate growth of
  skeletal and muscular systems

54
Thyroid Disorders Hypersecretion

• Increased thyroxine production
• Most common cause is Graves disease
• Abnormal antibodies resemble TSH and
  overstimulate thyroid
• Symptoms increased metabolic rate, nervousness,
  sweating, increased HR and BP

55
Thyroid Calcitonin
N

• Hormone type peptide
• Control parafollicular cells respond directly to
  increased plasma calcium (Ca2)
• Target bone
• Actions decreases plasma Ca2 by
• Inhibiting osteoclasts
• Stimulating osteoblasts

56
Parathyroid Gland

• Small, paired glands on posterior thyroid
• Hormone type peptide
• Control chief cells secrete parathyroid hormone
  (PTH) in direct response to decrease plasma Ca2
• Targets bone, kidney, intestine

Fig. 16.10, p. 623
57
Parathyroid Gland PTH Actions
Targets Actions
Bone Stimulates osteoclasts
Bone Inhibits osteoblasts
Kidney Stimulates Ca2 reabsorption
Intestine Stimulates Ca2 absorption (indirectly by increasing activation of vit. D)
58
Think-Pair-Share Calcium Regulation
Identify the hormones that affect plasma calcium levels for each indicate the stimulus for secretion and what effect the hormone has on plasma calcium Identify the hormones that affect plasma calcium levels for each indicate the stimulus for secretion and what effect the hormone has on plasma calcium Identify the hormones that affect plasma calcium levels for each indicate the stimulus for secretion and what effect the hormone has on plasma calcium
Hormone Stimulus Effect


59
Pancreas

• Retroperitoneal (Topic 1)
• Endocrine and exocrine (enzyme) secretion
• Acinar cells secrete enzymes into pancreatic
  ducts (AP II)
• Islets of Langerhans secrete hormones to
  regulate glucose levels
• Control humoral responses to plasma glucose
  levels

60
Pancreas

• Major cell types
• Alpha cells secrete glucagon
• Beta cells secrete insulin
• Delta cells secrete somatostatin (regulates
  digestion and secretion of insulin AP II)
• Think Spot What chemical type of hormone are
  these? How do they interact with their target
  cells?

Fig. 16.16, p. 631
61
Pancreas Control

• Alpha cells secrete glucagon
• Stimulation - decreased blood glucose and
  increased SD impulses
• Inhibition increased plasma glucose and
  somatostatin
• Beta cells secrete insulin
• Stimulation - increased blood glucose, fatty
  acids and PD impulses hyperglycemic hormones
  (increase blood glucose)
• Inhibition decreased plasma glucose

Fig. 16.17, p. 632
62
Pancreas Glucagon Actions
N
Targets Action Hyperglycemic
Liver Stimulates gluconeogenesis (formation of glucose from noncarbohydrate sources)
Liver Stimulates glycogenolysis (breakdown of glycogen)
Skeletal muscle Inhibits glucose oxidation
Skeletal muscle Stimulates glycogenolysis
Adipose Stimulates fat mobilization (triglyceride breakdown)
63
Pancreas Insulin Actions
Targets Action Hypoglycemic
Liver Inhibits gluconeogenesis
Liver Stimulates glycogen formation
Liver Does not stimulate uptake
Skeletal muscle Increases glucose uptake
Skeletal muscle Stimulates glycogen formation
Skeletal muscle Increases glucose oxidation
Adipose Converts glucose to fat
64
Pancreas Diabetes Mellitus

• Hyposecretion or hypoactivity
• Cells not stimulated to take up and use glucose
• Blood glucose increases (hyperglycemia)
• Symptoms arise as a result of hyperglycemia

65
Pancreas Diabetes Mellitus

• Type I - juvenile onset insulin-dependent
  diabetes mellitus
• Damage to beta cells prevents production
• Linked to viral infection and autoimmunity?
• Type II adult onset insulin-independent
  diabetes mellitus
• Body cells become less sensitive to insulin
• Associated with obesity, long-term ingestion of
  large quantities of sugar
• Initially controlled with diet and exercise

66
Pancreas Diabetes Mellitus
N

• Very high glucose (hyperglycemia) leads to nausea
  ? fight or flight response
• Fight or flight leads to secretin of
  hyperglycemic hormones (epinephrine from adrenal
  medulla cortisol from adrenal cortex)
• Causes further increase in plasma glucose
• Mobilizes fats

67
Pancreas Diabetes Mellitus
N

• Hyperglycemia leads to
• Glycosuria presence of glucose in urine)
• Glucose not completely reabsorbed, remains in
  urine (AP II)
• Polyuria excess urine production
• Increases solute concentration (AP II)
• Polydipsia excessive thirst
• Water loss causes increased plasma solute
  concentration (AP II)

68
Pancreas Diabetes Mellitus
N

• Fat mobilization
• Lipidemia increased concentration of fats in
  plasma causes vascular damage
• Ketonuria presence of ketone bodies
• Ketoacidosis decreased plasma pH caused by
  increased concentration of fatty acids and ketone
  bodies in blood (AP II)
• Depresses nervous system ? diabetic coma ? death
• Polyphagia due to use of fats and proteins as
  energy

69
Pancreas Hyperinsulinism

• Excess insulin (usually from injection of excess)
• Causes hypoglycemia
• Low brain glucose ? anxiety, nervousness,
  tremors, weakness, disorientation, death due to
  insulin shock

70
Gonads

• Reproductive organs
• Male testis (testes)
• Female ovary (ovaries)
• Hormones important to development of secondary
  sex characteristics
• Male large muscles, Adams apple (enlarged
  thyroid cartilage), hair distribution
• Female breast development, fat distribution

71
Gonads

• Controlled indirectly by hypothalamus through
  GnRH (controls pituitary)
• Think Spot
• What hormones exert direct control over
  production of gonadal hormones?
• What gland produces these hormones?

72
Gonadal Hormones Male

• Testosterone
• Converted to more active form called DHT
  (Dihydrotestosterone)
• Actions
• Maintenance of reproductive organs
• Development of secondary sex characteristics

73
Gonadal Hormones Female

• Estrogens and progestins (progesterone)
• Actions
• Estrogen development of ovary, uterus,
  secondary sex characteristics
• Progesterone with estrogen breast development,
  uterine cycle
• Both important to maintenance of endometrium
  during pregnancy

74
Adrenal Gland

• Retroperitoneal on superior border of kidney
• Surrounded by capsule
• Two regions
• Medulla
• Cortex

75
Adrenal Gland

• Medulla
• Inner region
• Neurosecretory cells (chromaffin cells) secrete
  catecholamines (Topic 5)
• Cortex
• Outer region
• 3 zones secrete corticosteroids

76
Adrenal Gland Development

• Medulla originates from same embryonic tissue
  as sympathetic ganglionic neurons
• Cortex develops from embryonic tissue called
  mesoderm

http//sprojects.mmi.mcgill.ca/embryology/ug/Adren
al_Stuff/Normal/zones.html
77
Adrenal Medulla

• Secretes catecholamines (Topics 5 9)
• Control release of neurotransmitter from
  sympathetic preganglionic fibers (Topic 9)
• Think Spot What type of control is this?
• Targets / Actions See Topic 9
• NE has greater effect on alpha receptors
• Epi has greater effect on beta receptors

78
Adrenal Cortex

• Secretes steroid hormones
• Three zones each with particular major hormone
  type
• Zona glomerulosa mineralocorticoids
• Zona fasciculata glucocorticoids
• Zona reticularis gonadal hormones
• Control
• ACTH stimulates secretion by all three regions
• Zona glomerulosa responds to plasma K /Na

79
Zona Glomerulosa
N

• Mineralocorticoids (aldosterone) control
  electrolyte and water balance (AP II)
• Control
• Stimulated by
• High plasma K /low plasma Na
• Angiotensin II (response to decreased BP)
• High ACTH levels
• Inhibited by low plasma K / high plasma Na
• Target kidney

80
Mineralocorticoid Actions

• Reabsorption (retention) of Na tied to secretion
  of K from kidney (also from sweat glands,
  salivary glands, pancreas)
• Increases obligatory water reabsorption by
  increasing plasma ion (Na) concentration

81
Mineralocorticoid Disorders
N

• Aldosteronism
• Hypersecretion of aldosterone alone
• Caused by adrenal tumor
• Results in
• Increased Na (and water) reabsorption leading to
  hypertension and edema
• Loss of K leading to neuron and muscle
  dysfunction

82
Zona Fasciculata

• Glucocorticoids (cortisol) control glucose
  metabolism
• Control
• Stimulated by ACTH
• Inhibited by rising cortisol levels (inhibits
  CRH levels of CRH peak in morning)
• Target liver (and muscle cells)

83
Glucocorticoid Actions
N

• Increases plasma glucose by acting on liver to
  stimulate gluconeogenesis
• Spares glucose (for brain) by stimulating use of
  alternatives for energy in cells (especially
  muscle)
• Increases anti-inflammatory response
• Suppresses immune system
• Used clinically to suppress inflammation but can
  lead to disease

84
Glucocorticoid Disorders
N

• Addisons disease
• Hyposecretion of cortisol and aldosterone
• Decreased aldosterone causes
• Decreased plasma Na, increased plasma K
• Decreased water reabsorption leads to
  hypotension, dehydration (low Na)
• Altered membrane potential (high K)
• Decreased cortisol causes hypoglycemia
  (especially during stress)

85
Glucocorticoid Disorders
N

• Cushings disease
• Hypersecretion of cortisol
• Caused by
• Zona fasciculata tumor
• Hypersecretion of ACTH due to pituitary gland
  problem or tumor
• Hypersecretion of ACTH due to cancer in certain
  other tissues (e.g., lung)

86
Glucocorticoid Disorders
N

• Cushings disease symptoms
• Decreased glucose use leading to hyperglycemia
  (steroid diabetes)
• Hypertension and edema
• Increased lipid metabolism
• Fat redistribution
• Buffalo hump
• Poor wound healing
• Moon face

87
Zona Reticularis

• Gonadocorticoids
• Testosterone (main)
• Estrogens (small amounts)
• Control stimulated by ACTH (note increase in
  gonadaocorticoids does not appear to decrease
  ACTH secretion)
• Actions unclear may be involved in onset of
  puberty

88
Think-Pair-Share Glucose Regulation
List the hormones that affect plasma glucose levels List the hormones that affect plasma glucose levels
Hyperglycemic hormones Hypoglycemic hormones




89
General Adaptation Syndrome

• Stress response same general response to
  different stressors
• Stress any condition that threatens homeostasis
  (real or perceived)
• Three phases
• Alarm
• Resistance
• Exhaustion
• Involves adrenal gland

90
GAS Alarm Phase

• Immediate response
• Hypothalamus activates sympathetic division and
  adrenal medulla
• Effects include
• Increased heart rate and blood pressure
• Increased blood glucose
• Bronchodilation
• Increased metabolic rate
• Altered blood flow (increased flow to muscles)

91
GAS Resistance Phase
N

• Weeks to months
• Hypothalamus (CRH) activates anterior pituitary
  (ACTH), which activates adrenal cortex
• CRH interferes with memory
• Effects are related to increased aldosterone
  (increased blood volume and pressure) and
  cortisol (increased blood glucose, immune
  suppression, use of fats and protein as fuel)

92
GAS Exhaustion Phase

• After months of stress
• Effects are related to
• Increased aldosterone (mineral imbalances)
• Cortisol depletion (overuse of lipid reserves)

93
Think-Pair-Share Blood Pressure Regulation
N
Identify the hormones that affect blood pressure by increasing water reabsorption (directly or indirectly) or by acting on the heart and blood vessels Identify the hormones that affect blood pressure by increasing water reabsorption (directly or indirectly) or by acting on the heart and blood vessels
Water reabsorption Act on heart and vessels