Endocrinology Flashcards
1
Q
Hormones
A
Mediator molecules that are released in one part of the body but that can regulate the activity of cells in other areas.
2
Q
Functions of hormones
A
- Regulation
- Control growth and development
- Regulate operation of reproductive systems
- Help establish circadian rhythm
3
Q
What do hormones regulate?
A
Chemical composition and volume of the internal environment.
Metabolism and energy balance
Contraction of smooth and cardiac muscle fibres
Glandular secretions
Some immune activity
4
Q
Nervous vs. Endocrine: Mediator molecules
A
Nervous: neurotransmitters released locally in response to nerve impulse
Endocrime: hormones delivered to tissue throughout the body by blood
5
Q
Nervous vs Endocrine: site of mediator action
A
Nervous: close to site of release; at synapse; binds to receptor in postsynaptic membrane
Endocrine: potentially far from site of release; binds to receptor in or on target cells
6
Q
Nervous vs Endocrine: types of target cells
A
Nervous: Muscle cells, glands, neurons
Endocrine: cells throughout the body that affect metabolism, regulate growth and development, and influence reproduction
7
Q
Nervous vs. Endocrine: time to onset of action
A
Nervous: usually within miliseconds
Endocrine: seconds to hours or days
8
Q
Nervous vs. Endocrine: duration of action
A
Nervous: generally brief
Endocrine: generally longer (seconds to days)
9
Q
Exocrine Glands
A
Epithelial cell(s) that secrete their products into ducts which carry them into body cavities, lumen, or outside of the body.
ex. sebaceous, mucous and digestive glands
10
Q
Endocrine Glands:
A
Epithelial cell(s) that secrete hormones into the surrounding interstitial fluid.
The hormones diffuse into capillaries and are carried to the target cells.
ex. pituitary, thyroid, parathyroid, adrenal and pineal glands
11
Q
Organs/tissue that secrete hormones but that aren’t exclusively endocrine
A
Hypothalamus Thymus Pancreas Ovaries/testes Kidneys Stomach Liver Small Intestine Skin Heart Adipose tissue Placenta
12
Q
How many receptors/target-cell?
A
2000-100000
13
Q
Down regulation
A
When a substance (like a hormone) is present in excess, the number of receptors may decrease
- some current receptors endocytosed and degraded
- target cell now less sensitive to the substance
ex. insulin resistance
14
Q
Up regulation
A
When the amount of a substance (like a hormone) is deficient, more receptors for that hormone are created, making the target tissue more sensitive.
15
Q
Paracrine hormones
A
Act on neighbouring cells
16
Q
Autocrine hormones
A
Act on the cell that secretes them
17
Q
Two broad classes of hormones:
A
Lipid and water soluble
18
Q
Three types of lipid soluble hormones
A
- Steroid hormones
- derived from cholesterol (lipid + 4 carbon rings)
- differ in attachment sites for chemical groups
ex. testosterone and estrogen
- derived from cholesterol (lipid + 4 carbon rings)
- Thyroid hormones (T3, T4)
- - made by attaching iodine to tyrosine
- - made very lipid soluble by two benzene rings - Nitric Oxide (NO)
- - neurotransmitter and hormone (like NE and epinephrine)
- - synthesis catalyzed by nitric oxide synthase
19
Q
Transporter proteins (hormone)
A
For lipid soluble hormones that can’t circulate freely in blood plasma.
- make lipid soluble hormones temporarily water-soluble,
- retard passage of small hormones through kidney filters, slowing rate of hormone loss
- provide reserve of hormone, always present in bloodstream
20
Q
Three types of water soluble hormones
A
- Amine hormones
- modified decarboxylated amino acids
- epinephrine, norepineprhine - Peptide and protein hormones
- amino acid polymers (peptide: 3-49; protein 50-200)
- - oxytocin (peptide) insulin and HGH (proteins) - Eicosanoid hormones
- - derived from arachidonic acid
- -important local hormones, but may circulate as well
- - prostaglandins (PG) [cycloxygenase pathway]
- - leukotrienes (LTs) [lipoxygenase pathway]
21
Q
Permissive Effect
A
Hormone A arrives. Weak effect.
Hormone B arrives; doesn’t act directly on target, but strengthens effect of A.
ex. epinephrine breaking down triglycerides with the help of T3/T4
22
Q
Synergystic Effect
A
Two hormones acting together have a greater or more more extensive effect than either alone. (FSH and estrogens –> oocyte development)
23
Q
Antagonistic effect
A
Two hormones doing the opposite thing.
Insulin stimulates glycogenesis
Glucagon stimulates glycogenelysis
24
Q
Activity of Lipid Soluble Hormones
A
- Free hormone diffuses through blood and interstitial fluid; diffuses though cell membrane into cytosol
- Binds to and activates receptor within nucleus or cytosol. Specific genes turned on or off
- DNA transcribed, new mRNA forms, and ribosomes synthesizes new protein (typically enzyme)
- Gene expression altered => new protein alter’s cell activity
25
Activity of Water Soluble Hormones
1. Hormone [1st Messenger] binds to receptor on cell membrane.
2. Receptor-hormone complex activates G protein
3. G protein activates Adenylate Cyclase
4. Adenylate Cyclase converts ATP --> cAMP [2nd Messenger]
5. cAMP activates Protein Kinase
6. Protein kinase phosphorylates cellular proteins, which activates some and inactivates others
7. Phosphorylated proteins case reactions which cause physiological responses
8. cAMP deactivated by phosphdiesterase
26
Why do hormones have such a large effect with such a low concentrations?
Water soluble can have a Cascade effect.
One hormone molecule can activate 100 G-proteins, each of which can activate 1000 cAMP, and each protein kinase can act upon 1000s of substrate molecules
27
Hormone secretion is regulated by:
1. signals from the nervous system
2. chemical changes in the blood
3. other hormones
28
Negative feedback and hormones
Most common.
ex. low blood glucose --> glucagon --> increased blood glucose --> no more glucagon
29
Positive feedback and hormones
Less common
ex. childbirth --> oxytocin --> contractions --> oxytoxin --> contractions --> etc.
30
Adenylate Cyclase
Catalyzes conversion of ATP to c-AMP during action of water soluble hormones
Activated by G-protein
31
Protein kinase
Phophorylates proteins within cell, creating effect of water soluble hormones. Uses ATP.
Activated by c-AMP
32
What deactivates c-AMP?
Phosphodiesterase
33
Hypothalamus
Lies below thalamus; major link between nervous and endocrine systems
Secretes at least 9 hormones
Regulates virtually all aspects of grown, development, metabolism and homeostasis
34
Pituitary gland
AKA hypophysis
Lies in hypophyseal fossa of sella turcica of sphenoid bone
Secretes at least 7 hormones
Consists of anterior and posterior portions
35
Anterior Pituitary
Adenohypophysis
Accounts for 75% of the weight of the pituitary.
Composed of epithelial tissue (derived from roof of pharynx)
Consists of: pars distalis and pars tuberalis
36
Posterior Pituitary
Neurohypophysis
Composed of neural tissue. Extension of diencephalon
Doesn't produce hormones; stores and releases oxytocin and ADH produced by hypothalamus
Consists of pars nervosa and infundibulum
37
Pars distalis
Largest portion of the anterior pituitary gland
38
Pars tuberalis
Part of anterior pituitary gland; forms sheath around infundibulum
39
Pars nervosa
Part of posterior pituitary gland
40
Infundibulum
Part of the posterior pituitary gland
| Connects hypothalamus with posterior pituitary
41
Hypophyseal Portal System
How hypothalamic hormones reach the anterior pituitary gland
Internal carotid artery --> [branches into]
Superior hypophyseal artery (brings blood to hypothalamus) --> [at hypothalamus/infundibulum junction branch into]
Primary Plexus of Hypophyseal Portal System receive hormones from the Tuberal Region of the hypothalamus (dorsomedial, ventromedial and arcuate/tuberal nuclei)--> [drains into]
Hypophyseal portal veins (passes down outside of infundibulum) --> [splits again to form]
Secondary Plexus of Hypophyseal Portal System
Anterior Hypophyseal Veins --> general circulation
42
Neurosecretory Cells
Specialized cells above the optic chiasm that synthesize hypothalamic releasing and inhibiting hormones .
Store hormones in vesicles in axons; nerve impulses cause vesicles to exocytose, and hormones then diffuse into the primary plexus of the HPS.
43
5 Types of Anterior Pituitary Cell
1. Somatotrophs
2. Thyrotrophs
3. Gonadotrophs
4. Lactotrophs
5. Corticotrophs
44
Somatotrophs
Anterior pituitary cells.
Stimulated by Growth Hormone Releasing Hormone (GHRH), aka somatocrinin
Inhibited by Growth Hormone Inibiting Hormone (GHIH), aka somatostatin.
Secrete hGH (aka somatropin), which act on liver cells to produce IGF
--> stimulation of body growth and metabolism regulation
45
Thyrotrophs
Anterior pituitary cells
Stimulated by Thyrotropin-releasing hormone (TRH).
[ May be inhibited by GHIH, depending on what page you're reading]
Secrete thyroid stimulating hormone (TSH, AKA thyrotropin), which act on the thryoid to control thyroid secretions
46
Gonadotrophs
Anterior pituitary cells
Stimulated by Gonadotropin Releasing Hormone (GnRH)
Secrete FSH and LH, which act on gonads
47
Lactotrophs
Anterior pituitary cells
Stimulated by Prolactin Releasing Hormone (PRH)
Inhibited by Prolactin Inhibiting Hormone (PIH), which is dopamine
Acts on mammary glands to stimulate milk production
48
Corticotrophs
Anterior pituitary cells
Stimulated by corticotropin releasing hormone (CRH)
Melanocyte production inhibited by dopamine
Produce Adrenocorticotropic Hormone (ACTH), AKA corticotropin which act on the adrenal cortex to secrete glucocorticoids (like cortisol).
Also produce melanocyte-stimulating hormone
49
Human Growth Hormone
Released by anterior pituitary somatotrophs
AKA somatotropin
Released every few hours (especially during sleep)
Controlled by GHRH and GHIH
Regulated by blood glucose level
Most plentiful anterior pituitary hormone
Promotes synthesis of (or is transformed into?) IGF
50
Functions of IGFs
1a Increases cellular uptake of amino acids and accelerates protein synthesis --> growth
1b Decreases breakdown of proteins and use of amino acids for ATP production --> fast growth during development
2. Enhances lipolysis
3. Decreases glucose uptake to ensure availability for ATP production
51
Besides blood glucose level, what things stimulate hGH synthesis?
Decreased fatty acids and increased amino acids in blood
Deep sleep
Increased SNS
52
Thyroid Stimulating Hormone
Produced by thyrotrophs in anterior pituitary
Controlled by TRH. Negative feedback via circulating T3/T4 levels
Stimulates synthesis of T3 and T4
53
Follicle Stimulating Hormone
FSH
Produced by gonadatrophs in anterior pituitary
Targets gonads.
Stimulated by GnRH.
In women, stimulates development of secondary ovarian follicles and estrogen release.
In men, stimulates sperm production
Negative feedback via estrogen/testosterone levels
54
Luteinizing Hormone
LH
Produced by gonadotrophs in anterior pituitary
Stimulated by GnRH
In women triggers ovulation, formation of corpus luteum, and release of progesterone.
In men, stimulates testosterone secretion.
55
Prolactin
Produced by lactotrophs in anterior pituitary.
Initiates and maintains milk secretion.
Regulated by PRH and PIH (dopamine)
Synergistic (?) effort with estrogens, progesterone, glucocorticoids, hGH, thyroxine and insulin.
56
When not pregnant, what happens with prolactin each month?
Just before menstruation, PIH decreases, prolactin increases, and boobs get sore
57
Adrenocorticotropic Hormone
ACTH
Released by corticotrophs in anterior pituitary.
Regulated by CRH
Acts on adrenal cortex to produce glucocorticoids like cortisol
58
Melanocyte-stimulating Hormone
MSH
Released by corticotrophs in anterior pituitary
Regulated by CRH (stimulatory) and dopamine (inhibitory)
Increases skin pigmentation and may influence brain activity
59
What nuclei in the hypothalamus supply the posterior pituitary?
Paraventricular (oxytocin)
| Supraoptic (ADH)
60
Hypothalamohyophyseal Tract
Axons from paraventricular and supraoptic nuclei, which extend to the blood capillaries in the posterior pituitary.
Paraventricular/supraorbital nuclei
Posterior pituitary
Capillary Plexus of Infundibular Process
Posterior hypophyseal vein
61
Oxytocin
Produced by paraventricular nucleus
Enhances contraction of smooth muscle cells in wall of uterus and stimulates milk ejection from mammary glands
62
Antidiuretic Hormone
ADH, or vasopressin
High osmotic pressure (decreased blood volume) stimulates osmoreceptors in hypothalamus. ADH secreted:
Works on:
1. kidneys (increased water reabsorption, reduced urination)
2. Sweat glands (decreases activity)
3. Smooth muscles in walls of arterioles -- constricts, increases BP
Low osmotic pressure (increased blood volume). ADH no longer secreted.
63
Thyroid Gland
Inferior to larynx
Mostly made up of thyroid follicles
Only endocrine gland that stores its product in large quantities
64
Thyroid follicles
Make up most of the thyroid gland
Microscopic spherical sacs surrounded by basement membrane
Wall composed of follicular cells, which are cuboidal or squamous when inactive, but cuboidal to columnar when under the influence of TSH
Produce thyroxine (T4) and triiodothyronine (T3)
65
Parafollicular Cells
C Cells in thyroid gland. Lie between follicles
| Produce calcitonin
66
Calcitonin
Produced by parafollicular/C cells in thyroid
Decrease circulating calcium by increasing increasing osteoblast activity, inhibiting resorption by osteoclases, and accelerating Ca+ reuptake.
67
Thyroid Hormone
Thyroxine/tetraiodothyronine (T4)
Triiodothyronine (T3)
Synthesized from iodine and tyrosine within thyroglobulin
Increase metabolism and protein synthesis
More T4 than T3 circulating, but T3 more potent.
(Most T4 converted to T3 inside cell)
68
Formation of Thyroid Hormone
1. Iodide trapping
2. Thyroglobulin synthesis
3. Oxidation of iodide
4. Oxidation of tyrosine
5. Coupling of T1 and T2
6. Pinocytosis and digestion of colloid
69
How does iodide enter follicular cell?
How does colloid re-enter follicular cell?
How does T3/T4 enter bloodstream?
Trapped and actively transported
Pinocytosis
Passive diffusion
70
Thyroglobulin
Large glycoprotein synthesized by the rough ER in the follicular cells and modified by the Golgi bodies.
Contain tyrosine, which attach to iodine
71
Colloid
Sticky material made when tyrosine on thyroglobulin is iodinated, forming T1 and/or T2
72
Control of Thyroid Hormone secretion
Low levels of T3/T4, or low metabolic rate -->
Hypothalamus releases TRH, which enters hypophyseal portal vein -->
Thyrotrophs in anterior pituitary release TSH -->
TSH stimulates all aspects of follicular cell activity -->
T3 and T4 released, situation regulated.
73
Functions of Thyroid Hormones
1. Increase BMR
2. Stimulates synthesis of Na/K pumps (Na-K ATPase)
3. Stimulates protein synthesis and use of glucose and fatty acids for ATP production. Increases lipolysis and cholesterol excretion (decreases blood cholesterol)
4. Enhances actions of catecholamines (epinephrine and NE) because they up-regulate beta receptors
5. Accelerates body growth (with hGH and insulin)
74
Calorigenic Effect
Increased ATP use --> increased heat
75
Hyperthyroidism: symptoms
Increased heart rate, more forceful heartbeats, increased BP
76
Miacalcin
Calcitonin extract derived from salmon that is 10x more potent than human calcitonin.
Rx for osteoporosis
77
Parathyroid Glands
Posterior surface of lateral lobes of thyroid gland
Each side has an inferior and superior lobe
Contains chief (principal) cells, which produce PTH, and oxyphil cells (function unknown)
78
Parathyroid Hormone
Increases circulating calcium (so opposes calcitonin)
Also major regulator of Mg+ and phosphate ions.
Increases number/activity of osteoclasts --> increase resorption
Also acts on kidneys (distal convoluted tubule)
79
How does PTH act on kidneys?
Slows rate of Ca+ and Mg+ loss
Increases phosphate loss (more lost in urine than gained from bone so net phosphate loss)
Promotes formation of calcitrol
80
Calcitrol
Active form of vitamin D
Synthesized in kidneys in response to PTH
Increases rate of Ca+, Mg+ and phosphate absorption from GI tract
81
How are calcitonin and PTH regulated?
Blood calcium level, negative feedback.
| Does NOT involve pituitary gland.
82
Adrenal Glands
Paired glands, superior to each kidney.
Retroperitoneal space.
Two functional regions: cortex and medulla
83
Adrenal Cortex
80-90% of the adrenal gland
| Produces steroid hormones
84
Adrenal Medulla
10-20% of the adrenal gland
Produces 3 catecholamine hormones (norepinephrine, epinephrine and dopamine)
85
Three zones of the adrenal cortex
1. zona glomerulosa
2. zona fasciculata
3. zona reticularis
86
Zona glomerulosa
Outer zone of the adrenal cortex
| Secrete mineralocorticoids.
87
Mineralocorticoids
Secreted by the zona glomerulosa of the adrenal cortex.
Steroid hormones that affect salt and water balance
Major mineralcorticoid is aldesterone
88
Renin-angiotensin-aldosterone (RAA) pathway
Dehydration, NA+ deficiency, hemorrhage (decreased blood volume)
- -> decreased blood pressure
- -> juxtaglomerula cells secrete renin
- -> renin converts angitensinogen (produced by liver) into angiotensin 1
- -> in capillaries, angiotensin converting enzyme (ACE) converts angiotensin 1 into angiotensin 2, which stimulates
- -> adrenal cortex to secrete ALDOSTERONE, which
- -> increases reabsorption of Na+ and H2O, and secretion of K+ and H+, which
- -> increases blood volume and hence pressure
89
Aldesterone
MIneralocorticoid secreted by zona glomerulosa of the adrenal cortex.
Stimulated by increased K+ levels and by angiotensin 2 (which is formed because of low blood pressure)
Acts on principle cells in DCT. Stimulates reabsorption of Na+ and water, and secretion of K+ and H+
90
Zona fasciculata
Widest zone of the adrenal cortex. Middle layer; cells in long, straight columns
Secretes mainly glucocorticoids
91
Glucocorticoids
Steroid hormones that act to regulate glucose metabolism. Secreted by zona fasciculata layer of the adrenal cortex.
Include cortisol (most abundant), corticosterone, and cortisone
Low circulating glucocorticoids/stress--> CRH release by hypothalamus --> ACTH release from anterior pituitary
92
Effects of glucocorticoids
1. Protein breakdown
2. Glucose formation (gluconeogenesis)
3. Lipolysis
4. Resistance to stress
5. Antiinflammatory effects (inhibit WBCs)
6. Immune response depression
93
Zona reticularis
Deepest layer of adrenal cortex.
Secrete small amounts of weak androgens. After menopause, only source of female estrogens
94
Androgens
Steroid hormones that control development and maintenance of male sexual characteristics in vertebrate. In females affects libido and is converted to estrogen
Zona reticularis secretes dehydroepiandrosterone (DHEA)
95
Adrenal Medulla
Inner part of the adrenal gland.
Modified ganglion of the ANS --> neural tissue without axons; clusters around blood vessels.
ANS sympathetic preganglionic fibres innervate chromaffin cells, which release epinephrine and norepinephrine.
96
Epinephrine and Norephinephrine
Can act as either a neurotransmitter or hormone.
As hormones, released by adrenal medulla, intensify sympathetic responses in other parts of the body.
Stress/exercise --> hypothalamus --> sympathetic preganglion nerves --> chromaffin cells
97
Effects of epinephrine and NE
--> increase rate and force of heart contraction, increase BP, increase blood flow to heart, liver, skeletal muscles and adipose tissue, dilate airways and increase circulating glucose and fatty acids
98
Pancreatic Islets
Pancreas is both exocrine (acini) and endocrine islets (only 1% of the organ)
1-2 million/pancreas
99
Types of pancreatic islet cells
1. Alpha (A) 17% -- glucagon
2. Beta (B) 70%-- insulin
3. Delta (D) 7%-- somatostatin
4. F cells 6%-- pancreatic polypeptide
100
Glucagon
Released by alpha pancreatic islet cells in response to hypoglycemia and/or rise in blood amino acids
Increases blood glucose levels by acting on liver cells to promote glycogenolysis and gluconeogenesis
101
Insulin
Released by the beta pancreatic islet cells in response to hyperglycemia.
Acts on various cells in the body to accelerated facilitated diffusion of glucose into cells, to speed the glycogenesis, and to increase uptake of amino acids into the cell to increase protein synthesis. Also speeds synthesis of fatty acids, and slows glycogenolysis and gluconeogenesis
Also suppresses glucogon secretion
102
What other hormones/chemicals stimulate insulin secretion?
ACh (the NT released by the vagus nerve, which innervates the pancreatic islets)
hGH and ACTH (elevate blood glucose)
Arginine and Leucine (amino acids -- present after eating protein)
Glucose-dependent insulinotropic peptide (GIP) - released by enteroendocrine cells in response to glucose
103
Hormones released by the ovaries
Steroid hormones, including
2 estrogens *estradiol and estrone)
Progesterone
With FSH and LH--> menstrual regulation, preparation and maintenance of pregnancy, preparing mammary glands from lactation
Also produce Inhibin (inhibits secretion of FSH) and, during pregnancy, relaxin
104
Hormones released by testes
Testosterone (regulates sperm production, stimulates development of secondary sexual characteristics)
Inhibin (inhibits FSH)
105
Pineal Gland
Roof of third ventricle, between superior colliculi, covered by pia mater.
Consists of neuroglia and pinealocytes
Releases melatonin (amine hormone derived from seratonin)--> sleepiness
More released during darkness, and while asleep
106
Pinealocytes
Secretory cells in pineal gland; secrete melatonin
107
Thymus
Located between lungs, behind sternum, in mediastinum
Mostly immunological role
```
Produces:
Thymosin
Thymic Humoral Factor (THF)
Thymic Factor (TF)
Thymopoietin
```
All promote maturation of T cells
108
Eicosanoids
Two main families: prostaglandins (PGs) and leukotrienes (LTs)
Every cells except RBCs
Synthesized from arachidonic acid (from membrane phospholipids)
Bind to membrane receptors and either inhibit or stimulated the synthesis of secondary messengers (like cAMP)
109
Leukotrienes
LTs
Eicosanoid molecules
Stimulate chemotaxis of WBC and mediate inflammation
110
Prostaglandins
PGs
Eicosanoid molecules
Alter smooth muscle contractions, glandular secretions, blood flow, reproductive processes, plate function, respiration, nerve impulse transmissions, lipid metabolism and immune response.
111
Growth Factors
Mitogenic -- stimulate cell division
Mostly autocrine or paracrine
```
6 important:
Epidermal GF (EGF)
Platelet derived GF (PDGF)
Fibroblast GF (FGF)
Nerve GF (NGF)
Tumor angiogenesis factors (TAF)
Transforming growth factors (TGFs)
```
112
Epidermal growth factor
Produced in salivary glands
Stimulates proliferation of epithelial cells, fibroblasts, neurons and astrocytes.
Suppresses gastric juice secretion and some cancer cells
113
Platelet derived growth factor
Produced in platelets
Stimulates proliferation of neuroglia, smooth muscle fibres and fibroblasts.
Maybe wound healing and atherosclerosis
114
Fibroblast growth factor
Pituitary gland and brain
Proliferation of cells from mesoderm (fibroblasts, adrenocortical cells, smooth muscle fibres, chondrocytes, endothelial cells) and stimulates angiogenesis
115
Nerve growth factor
Salivary glands and hippocampus
Growth of embryonic ganglia; neural hypertrophy and differentiation
116
Tumor angiogenesis factors
Stimulates angiogenesis, organ regeneration and wound healing in normal and tumour cells
117
Transforming growth factors
Alpha -- like EGF
Beta -- inhibits proliferation
118
General Adaptation Syndrome
Stress response; the normal sequential homeostatic mechanisms which occur in response to stress
```
Controlled by hypothalamus
Three stages:
1. Fight or flight
2. Resistance
3. Exhaustion
```
119
Fight or flight
Nerve impulse from hypothalamus to sympathetic NS
--> adrenal medulla --> NE and epinephrine
Increased glucose and O2 to vital organs (brain, skeletal muscles, heart)
Decreased blood flow to kidneys --> RAA pathway -->increased BP
120
Resistance Reaction
Hypothalamic releasing hormones. Longer than Fight or Flight.
CRH
GHRH
TRH
--> increased available glucose, decreased inflammation,
121
Exhaustion
Loss of potassium, depletion of glucocorticoids, weakened organs.
Body cannot sustain resistance.
Prolonged exposure to high cortisol etc --> muscle wasting, immune suppression, ulceration of GI tract, failure of pancreatic beta cells (insulin)
122
Pituitary Dwarfism
Hyposecretion of hGh during growth years
| Organs fail to grow; childlike proportions
123
Giantism
Hypersecretion of hGH during growth years.
| Abnormal increase in length of long bones; normal proportions.
124
Acromegaly
Hypersecretion of hGH during adulthood.
Epiphyseal plates already closed --> bones of hands, feet, cheeks, etc. thicken; eyelids, lips, tongue and nose enlarge, skin thickens.
125
Diabetes insipidus
Defect in ADH receptor (nephrogenic) or inability of posterior pituitary to secrete ADH (neurogenic).
Excessive urination, dehydration.
126
Congenital hypothyroidism
Present at birth. (cretinism) Hyposecretion of thyroid hormone
Severe mental retardation, stunted bone growth.
May present normally at birth because of presence of mother's hormones
127
Myxedema
Presentation of adult hypothyroidism
Women 5x men
Edema, bradycardia, low body temperature, cold sensitivity, dry hair and skin, muscular weakness, lethargy, weight gain. Reduced alertness
128
Graves disease
Most common form of hyperthyroidism.
Autoimmune -- antibodies mimic TSH
Women > men
Goiter, exopthalmos
129
Goiter
Enlarged thyroid gland
130
Hypoparathyroidism
Low levels of PTH --> low circulating Ca+ --> depolarizing neurons
--> twitches, spasms, tetany
131
Hyperparathyroidism
Elevated PTH --> soft, brittle bones
Most often from tumour
132
Cushing's Syndrome
Hypersecretion of cortisol by adrenal cortex
Breakdown of muscle proteins and redistribution of body fat --> spindly arms and legs; moon face, buffalo hump, pendulous abdomen.
133
Addison's Disease
Hyposecretion of glucocorticoids and aldosterone
Autoimmune --> antibodies cause adrenal cortex destruction and/or block ACTH binding sites.
Asymptomatic until destruction severe (90%)
Mental lethargy, anorexia, nausea, vomiting, weight loss, hypoglycemia, muscular weakness. Bronzed skin.
134
Pheochomocytomas
(Usually) benign tumuors of the chromaffin cells.
Hypersecretion of epinephrine, NE.
Tachycardia, high BP, elevated BMR
135
Diabetes Mellitus
Inability to produce or use insulin
Polyuria, polydipsia, polyphagia
136
Type 1 Diabetes
Pancreatic beta cells destroyed --> low insulin
Formally "insulin-dependent" or "juvenile"
Increased fatty acid breakdown --> buildup of ketone bodies --> decreased pH ---> ketoacidosis
137
Type 2 Diabetes
Formally "adult onset". Mostly lifestyle related
Insulin supply adequate, but cells less sensitive to it due to down regulation of insulin receptors
138
Hyperinsulinism
Most often from overmedication
--> hypoglycemia (too much uptake of glucose by body cells)
Anxiety, sweating, tremour, tachycardia, hunger, weakness.
