AP2 Exam 3

Question 1

Some mediators can be both a neurotransmitter and a hormone: what are some examples?

Answer 1

NE

Epi

Oxytocin: as a neurotransmitter, released throughout the brain and expressed by neurons

Question 2

Exocrine glands secrete their product into ______ that release into body cavities, lumen of organs, or to outer surface.

Answer 2

ducts

Question 3

Local hormones:

Answer 3

• act on neighboring cells or the same cell without entering the bloodstream
• paracrine: act on neighboring cell
• autocrine: act on same cell

Question 4

Amino acids:

Answer 4

• amines
• peptides
• proteins
  *

Question 5

Amino acid hormones:

Answer 5

• water soluble
  
  • unbound in the blood
  • cannot bass through cell membrane
  • bind to receptors on the outside/surface of the cell
  • second messenger
• derived from modification of one or multiple AAs

Question 6

Steroid/cholesterol hormones:

Answer 6

• lipid soluble
  
  • must be bound to transport proteins in the blood
  • provide a ready reserve of hormone in the blood
  • can freely pass through cell membrane
  • binds to receptors on the inside of the cell
• derived from cholesterol

Question 7

Steroid hormones

Answer 7

calcitriol

aldosterone

cortisol/corticosterone/cortisone

androgens: test., androstenedione, dihydrotestosterone (DHT), dehydroepiandrosterone (DHEA), DHEA sulfate

estrogen/progesterone

Question 8

Synthetic thyroid hormone is ______.

Answer 8

lipid soluble

taken orally; easily absorbed through intestinal wall

bioavailability is drastically reduced when transdermal/INJ (because all the membranes it has to travel through)

Question 9

Insulin is ______.

Answer 9

water soluble

cannot survive acidic environment in the stomach (destroys peptide bonds)

must be INJ SQ

Question 10

Hypothalamus (picture):

Answer 10

• controls the ANS through neural and hormonal approaches
• connected to the pituitary via the infundibulum:
  
  • infundibular stalk + pars tuberalis = indundibulum
    
    • hypothalamus and posterior pituitary connected via infundibular stalk
    • pars tuberalis of the anterior pituitary wraps up the infundibular stalk

Question 11

Hypothalamic Axes:

Answer 11

• Adrenal Axis
• Gonadal Axis
• Thyroid Axis
• Others are not a part of an axis but rather controlled by circulating levels of other hormones
  
  • Example: PTH, calcitonin, calcitriol

Question 12

Releasing and inhibiting hormones of the hypothalamus:

Answer 12

The Pretty Dressed Girl Got Some Courage

• Thyrotropin releasing hormone (TRH)
• Prolactin releasing hormone (PRH)
• Dopamine; Prolactin inhibiting hormone (PIH)
• Growth hormone releasing hormone (GHRH)
• Gonadotropin releasing hormone (GnRH)
• Somatostatin: Growth hormone inhibiting hormone (GHIH)
• Corticotropin releasing hormone (CRH)

Question 13

The pituitary gland:

Answer 13

• aka hypophysis
• sits in the sella turcica of the sphenoid bone
• anterior pituitary aka adenohypophysis aka pars distalis (the gland)
  
  • pars tuberalis partially covers the infundibulum like a sheath
• posterior pituitary aka neurohypophysis aka pars nervosa

Question 14

Posterior pituitary:

Answer 14

• Antidiuretic hormone (ADH) and oxytocin are stored and released here
  
  • these two hormones are produced in the hypothalamus and sent via the axons (infundibular stalk) to the terminal ends (posterior pituitary) where they are stored

Question 15

Antidiuretic hormone (ADH)

Answer 15

• aka vasopressin
• effects:
  
  • anti diuresis (U/O can increase to 20L/day without ADH)
    
    • increased reabsorption in collecting ducts
  • inhibits sweat production>decreased water loss
  • systemic vasoconstriction of arterioles (smooth muscle)
• amount secreted varies with blood osmotic pressure and blood volume
  
  • monitored by osmoreceptors in hypothalamus
  • osmotic pressure increases with “thicker fluid”
• may also be secreted in response to: pain, stress, anxiety, morphine, tranquilizers, anesthetics, nicotine

Question 16

Diabetes Insipidus

Answer 16

• defects of ADH receptors or inability to produce/secrete ADH
  
  • neurogenic DI: reduction/cessation of production/secretion of ADH (tumor, trauma, surgery)
  • nephrogenic DI: kidneys don’t respond to the ADH
    
    • non functional receptors in kidneys or kidney damage

*can die in a day from dehydration

Question 17

Oxytocin

Answer 17

• childbirth (stretching of uterus stimulated secretion)>pos. feedback
• stimulates milk ejection (let down) in response to suckling
• may be involved with:
  
  • emotional/social bonding with others
  • parenting (levels increased in new moms/dads)
  • autism (many have low oxytocin levels but not all)
  • sexual pleasure during/after (length/strength of orgasm and post coital)
    
    • no affect on sexual arousal, erection, sex drive

Question 18

Anterior pituitary:

Answer 18

• aka adenohypophysis aka pars distalis
• secretes hormones from 5 types of cells:
  
  • somatotrophs: human growth hormone (hGH) aka somatropin
  • thyrotrophs: thyroid stimulating hormone (TSH) aka thyrotropin
  • gonadotrophs: follicle stimulating hormone (FSH); luteinizing hormone LH)
  • lactotrophs: prolactin (PRL)
  • corticotrophs: melanocyte stimulating hormone (MSH); adrenocorticotropic hormone (ACTH) aka corticotropin

Question 19

Human growth hormone (hGH)

Answer 19

• aka somatotropin (secreted by somatotrophs)
• most abundant anterior hormone
• targets most cells in the body rather than a particular gland/organ
• produced and released in a pulsatile/diurnal manner (increase during first 2hrs of sleep)
• main function is to promote synthesis/secretion of insulin-like growth factors (IGFs aka somatomedins) by cells in the body (liver, muscle, bones, etc)
  
  • (believed) most changes seen in body are due to IGFs rather than hGH directly
    
    • someone can have nml hGH but low IGFs>abnormalities
  • IFG functions of note:
    
    • adipose tissue: lypolysis> increased fatty acids released> used over glucose (more so during fasted state)
    • skeletal muscle: suppresses protein catabolism; favors fatty acid use over glucose
    • immune: stimulates B and T cell function
    • metabolism: can cause beta cell burnout from extended insulin production (diabetogenic)
• secretion decreases with age
  
  • muscle wasting, unwanted fat

Question 20

Disorders of human growth hormone (hGH):

Answer 20

• Hypersecretion
  
  • giantism (gigantism)
    
    • hypersecretion in childhood stimulates chondrogenesis in epiphyseal plates
      
      • results in very tall with normal body proportions
    • will also normally experience:
      
      • hyperglycemia leading to insulin burnout (diabetes)
      • panhypopituitarism: hypertrophy of somatotrophs which eventually render the whole gland dysfunctional
  • acromegaly
    
    • hypersecretion in adulthood
      
      • enlargement of many internal organs (liver, kidneys)
      • thickened skin
      • bone thickening (enlarged facial features, feet, fingers)
• Hyposecretion
  
  • dwarfism
    
    • hyposecretion in childhood
      
      • epiphyseal plates close before nml heigh is attained
      • some keep child like characteristics whereas others can develop some adult characteristics with the addition of androgens

Question 21

Prolactin (PRL)

Answer 21

• pregnancy:
  
  • stimulates growth/development of mammary glands
  • synthesis of milk
• PRH stimulated by high levels of estrogen and suckling
• dopamine/PIH stimulated by low-moderate levels of estrogen
• Disorders:
  
  • hypersecretion most commonly caused by a prolactinoma (benign pituitary adenoma)
    
    • non pregnant, non breastfeeding female complaining of milky discharge
    • male with milky breast discharge or ED with no obvious cause

Question 22

Follicle stimulating hormone (FSH)

Answer 22

• females:
  
  • stimulates follicle production in women monthly
  • stimulates ovarian follicular cells to produce estrogen
• males:
  
  • stimulates production of sperm cells
• regulated by neg. feedback by estrogen and testosterone

Question 23

Luteinizing hormone (LH)

Answer 23

• females:
  
  • triggers ovulation
  • triggers formation of corpus luteum>secretion of progesterone
  • triggers secretion of estrogen by ovarian follicular cells (along with FSH)
• males:
  
  • stimulates testes to produce testosterone

Question 24

MSH

Answer 24

• peptide hormone produced not only in the anterior pituitary but also in the skin itself
• exact role of anterior pituitary produced MSH in humans unknown
  
  • possible appetite suppression
• MSH is produced locally in the skin>pigmentation of skin (melanin)
• dopamine (PIH) inhibits MSH release

Question 25

Thyroid gland and thyroid hormone:

Answer 25

• largest of “pure” endocrine glands (very extensive blood supply)
• only endocrine gland that stores its hormones in large quantities (~100day supply)
• follicles are the functional unit
• parafollicular cells reside in between follicles
  
  • produce calcitonin (not considered “thyroid hormone”)
    
    • inhibits calcium breakdown in bone and absorption in the intestines (closes certain channels)
    • increases calcium loss in urine (DCT)
• Thyroid hormones
  
  • production stimulated by TSH (inhibited via neg. feedback)
  • anything that increases cellular energy demand causes increase in T3/T4 production (cold, hypoglycemia, altitude, pregnancy)
  • Tetraiodothyronine (Thyroxine, T4)
    
    • inactive form of thyroid hormone
    • more abundant but less potent
  • Triiodothyronine (T3)
    
    • active form of thyroid hormone
    • less abundant but more potent

Question 26

Resorption vs. Reabsorption/Absorption

Answer 26

• Resorption: back into the blood
• Reabsorption/Absorption: out of the blood

Question 27

Synthesis and transport of T3/T4 (picture with steps):

Answer 27

• Follicular cells trap and pull iodide ions into the cytosol.
• Follicular cells are simultaneously producing the glycoprotein, thyroglobulin (TGB):
  
  • TGB is produced in the RER, modified in the Golgi body, and secreted into the colloid via exocytosis
• Iodide is oxidized into iodine by perioxidase then move into the colloid
• Iodine binds to the tyrosines that are part of the TGB
  
  • Monoiodotyrosine (MIT, T1): one iodine binds
  • Diiodotyrosine (DIT, T2): two iodines bind
• Coupling of T1 and T2:
  
  • T1+T2=T3 or T2+T2=T4
• Pinocytosis and digestion of colloid; lysosomes cleave off T3 and T4 molecules
  
  • Left over T1 and T2 are deiodinated and recycled
• Secretion of T3 and T4
• Transported in the blood via proteins produced in the liver
  
  • Thyroxine binding globulin (TBG) (70%)
  • Albumin (20%): generic transport protein
  • Transthyretin (10%): releases T3/4 into the CSF

Question 28

T3/T4

Answer 28

• transported by one of these proteins (all made in liver)
  
  • thyroxine binding globulin (TBG) (70%)
  • albumin (20%)
  • transthyretin (10%): releases thyroid hormone into CSF
• actions
  
  • increases BMR
    
    • rate of O2 consumption under normal conditions
  • stimulates synthesis of additional Na+/K+ pumps
    
    • increased ATP production and consumption>increased heat>maintain body temp
  • regulate metabolism
    
    • stimulates protein synthesis, lipolysis, cholesterol secretion
      
      • increases glucose and fatty acid use for ATP production
  • enhances actions of some catecholamines
    
    • T3/T4 upregulate beta receptors> increased HR, BP
  • works with hGH and insulin to accelerate body growth
    
    • nervous and skeletal
    • deficiency can result in mental retardation and stunted bone growth (fetal growth)>cretinism

Question 29

Hypothyroidism

Answer 29

• myxedema:
  
  • accumulation of negatively charged mucopolysaccharides in connective tissues (attracts sodium>fluid follows)
  • puffy features, enlarged tongue, hoarseness, joint stiffness
  • increased chance for effusions (serous cavities)
• cretinism (untreated congenital hypothyroidism)
  
  • associated with stunted growth, mental retardation, impaired motor neuron dysfunction, constipation (severe)
  • usually caused by severe lack of iodine or immune dysfunction
• Hashimoto’s disease
  
  • autoimmune
  • Ab attack TSH receptors and thyroglobulin
  • apoptosis of follicular cells
  • thyroid tissue becomes infiltrated with B and T cells
  • goiter

Question 30

Hyperthyroidism

Answer 30

• Grave’s disease
  
  • autoimmune
  • caused by production of thyroid stimulating Ig (autoantibody)
    
    • mimics TSH at TSH receptors excessively>overstimulation of thyroid gland
  • goiter
  • exophthalmos and periorbital edema (bug eyes)
    
    • orbital fibrocytes have TSH receptors>autoantibody stimulates these causing edema
  • thyroid will burn itself out if TSH receptors are constantly stimulated by autoantibody>becomes hypothyroidism
  • Tx: removal of thyroid tissue and supplementation with T4

Hyper can turn to hypothyroidism quickly (its rare for it to go the other way)

Question 31

Parathyroid glands:

Answer 31

• chief cells are the functional cell
  
  • produce and secrete parathyroid hormone (PTH)
    
    • resorb calcium from bone

Question 32

Adrenal glands:

Answer 32

• covered by connective tissue capsule
• adrenal cortex:
• adrenal medulla:

Question 33

Adrenal cortex:

Answer 33

• zona glomerulosa
  
  • mineralocorticoids
    
    • ACTH can stimulate however angiotensin2 and hyperkalemia stimulate to greater degree
    • aldosterone targets nephron
      
      • promotes filtration of K+ and H+ in urine
      • promotes reabsorption of Na+ in urine
• zona fasciculata
  
  • glucocorticoids
    
    • stress management (overreaction if stressor not removed)
    • cortisol (95%), corticosterone, cortisone
    • normal levels>stimulate:
      
      • gluconeogenesis
      • protein catabolism
      • lipolysis
    • excess levels cause:
      
      • inhibits bone formation
      • inhibits connective tissue formation
      • suppress immune response
        
        • suppress Ab formation, cell mediated immunity, kills immature T cells and B cells
        • anti-inflammatory
          
          • inhibits inflammatory cytokines>delays healing
          • stimulates anti-inflammatory cytokines (good under normal stress conditions)
• zona reticularis
  
  • androgens (weak variety)
    
    • dehydroepiandrosterone (DHEA)
      
      • precursor to numerous hormones: androstenedione, testosterone, dihydrotestosterone (DHT), estrogen
    • androstenedione
      
      • can be converted to: testosterone or estrone (precursor to estradiol)

Question 34

Disorders of adrenal cortex:

Answer 34

• Addison’s disease:
  
  • autoimmune attacks ACTH receptors
    
    • hyposecretion of gluco/mineralcorticoids
  • symptoms don’t present until 90% of cortex is destroyed
    
    • low aldosterone: hypoglycemia, anorexia>weight loss
    • low cortisol: hyperkalemia, acidosis, hypotension
    • low androgens: more noticeable in women>loss of pubic/axillary hair, decreased libido
    • increased circulating ACTH and MSH
      
      • distinct bronzing of the skin
      • hyperpigmentation of gums
• Cushing’s
  
  • Disease: increased ACTH from pituitary>increased cortisol
  • Syndrome: increased cortisol from adrenal glands without increased ACTH (or even exogenous corticosteroids>organ transplant, chronic inflammatory conditions)
  • Both result in:
    
    • muscle breakdown
    • redistribution of body fat
    • moon face
    • HTN (80%), hyperglycemia, osteoporosis, immunodeficiency, mood swings

Question 35

Adrenal medulla:

Answer 35

• functional cells are Chromaffin cells
  
  • considered modified sympathetic ganglion
    
    • signal received through splanchnic nerves>Ach binds to nicotinic receptors
  • produce/secrete catecholamines
    
    • epinephrine (more numerous and potent) and NE
    • intensify sympathetic responses throughout the body
      
      • stimulates glycogenolysis

Question 36

Disorders of adrenal medulla:

Answer 36

• pheochromocytoma
  
  • usually caused by a benign tumor of the chromaffin cells
    
    • most often arise in adrenal medulla however they can arise anywhere along sympathetic ganglia
  • prolonged “fight or flight” response

Question 37

Pancreas

Answer 37

• both exocrine and endocrine gland
• head, body and tail
• Islets of Langerhans (pancreatic islets)
  
  • 4 types of islet cells
    
    • alpha (20% of cells): glucagon
      
      • raise blood glucose levels (receptors in pancreas)
        
        • glycogenolysis and lipolysis
        • regulated by neg. feedback
        • short lived (liver deactivates very fast> first pass of portal blood)
    • beta (75% of cells): insulin
      
      • presence of food in small intestine triggers release of glucose-dependent insulinotropic peptide (GDIP)
      • lowers blood glucose levels
        
        • facilitates glucose uptake into cells
        • stimulates glycolysis and glycogenesis
        • neg. feedback
        • little longer lasting than glucagon (liver deactivates> first pass of portal blood)
• delta: somatostatin (GHIH)>actions concentration based
  
  • acts in paracrine manner by inhibiting both insulin/glucagon
• F: pancreatic polypeptide> actions concentration based
  
  • inhibits: somatostatin release, gallbladder contraction, secretion of enzymes and bicarb from pancreas
  • possible role in appetite suppression

Question 38

Disorders of pancreas:

Answer 38

• Growth:
• Diabetes mellitus: inability to produce or use insulin
  
  • type 1: autoimmune attacks beta cells>no insulin
    
    • symptoms do not show until 80-90% destruction
      
      • 3 P’s and possible DKA
  • type 2:
    
    • cells have less insulin receptors>insulin levels increased, increased blood glucose
    • usually obese
    • more mild symptoms (usually found with labs)
• Hyperinsulinism
  
  • usually occurs when diabetic injects too much insulin> results in hypoglycemia> causes secretion of epi, glucagon, hGH
    
    • symptoms: AMS
• Hyper and hypoglycemia can present similarly

Question 39

Gonads

Answer 39

• Ovaries
  
  • synthesize/secrete:
    
    • estrogen, progesterone: along with LH/FSH regulate menstrual cycle, maintain pregnancy, lactation
    • inhibin, relaxin>only produced in large qty in pregnancy
      
      • inhibin: inhibits FSH>deters follicle development
      • relaxin: relaxes cartilage of pubic symphysis, widen cervix>prepare for delivery
• Testes
  
  • synthesize/secrete:
    
    • testosterone
      
      • stimulates decent of testes before birth
      • regulates production of sperm and secondary sex characteristics
    • inhibin
      
      • high concentration: inhibits spermatogenesis
      • low concentration: reduces rate of spermatogenesis

Question 40

Pineal gland

Answer 40

• secretes melatonin
  
  • sets biological clock
    
    • more secreted in dark light>promotes sleepiness
• seasonal affective disorder (SAD)
  
  • type of depression worse in winter months and in areas that have more darkness (Alaska very long periods of darkness)
    
    • increased melatonin levels
  • Tx: bright light therapy

Question 41

Atrial natriuretic peptide/hormone (ANP/ANH)

Answer 41

• secreted by the heart when atria are stretched>reduces blood pressure

Question 42

Kidney hormones

Answer 42

Renin: stimulates the release of aldosterone

Calcitriol: increased Ca2+ absorption in the GI

Erythropoietin: stimulates RBC synthesis in bone marrow

Question 43

Adipose tissue hormones:

Answer 43

Leptin: promotes satiety signal to brain

Adiponectin: helps to reduce insulin resistance

Question 44

Cholecalciferol is produced by the ______.

Answer 44

skin

modified from of Vit. D

Question 45

Thymus hormones:

Answer 45

• atrophies with age
• produces multiple hormones that promote maturation of T cells
  
  • thymosin
  • thymic humoral factor
  • thymic factor
  • thymopoietin

Question 46

Misc. liver hormones:

Answer 46

• IGF
• angiotensiongen
• thrombopoietin: PLT’s
• Hepcidin: blocks release of iron into body fluids

Question 47

Digestive tract hormones

Answer 47

• gastrin:
  
  • promotes H+ section from parietal cells and growth of gastric mucosa
• cholecystokinin:
  
  • gallbladder contraction
  • slows gastric emptying
  • stimulates pancreatic enzyme release
• Glucose dependent insulinotropic peptide (GDIP/GIP):
  
  • stimulates insulin release
  • inhibits H+ ion secretion in gastric mucosa
• Secretin:
  
  • stimulates secretion of: pancreatic and biliary bicarb
  • inhibits effects of gastrin

Question 48

Eicosanoids

Answer 48

• found everywhere except RBC
• act as paracrine/autocrine
• very short lived (rapid deactivation)
• prostaglandins: smooth muscle, glands, blood flow, PLTs, TAGs, immune
• leukotrienes: mediates inflammation and chemotaxis of WBC

Question 49

Histamine

Answer 49

• synthesized in mast cells and platelets (most tissues)
  
  • from trauma (burns)
  • immune response
• functions
  
  • contraction of smooth muscle in lungs, uterus, stomach
  • vasodilation
  • stimulates gastric acid secretion
  • iflammation>increases permeability (immune)

Question 50

Serotonin

Answer 50

• synthesized by cells in the intestines (90%; bacterial colonies), brain, CNS
• platelets take up and store free serotonin until its needed (no production)
• stimulated by:
  
  • mood, anxiety, sleep
  • general body mvmt
  • GI motility
  • can acts as vasocontrictor/dilator depending on concentration

Question 51

General Adaptation Syndrome

Answer 51

• Alarm stage:
  
  • min-hrs
  • initiated by any stressor
  • cortisol release (impairs immune response)
  • SNS stimulated
• Resistance reaction (“recovery phase”)
  
  • hrs-weeks
  • stressor removed but dealing with psychological aftermath
    
    • cortisol levels should decline (immune system back to nml)
    • SNS stimulation is reduced
    • increased parasympathetic (rest and digest)
• Exhaustion response
  
  • if stressor is not removed or when resistance reaction not sufficient
  • depletion of physical/psychological energy levels
    
    • physical and mental illnesses begin to surface (ulcers, immunocompromise, depression, fatigue)
  • prolonged cortisol (immunocompromise)
  • prolonged SNS stimulation

*view body as a complete, integrated system>treat the whole person/body> treat underlying root causes of disease

Question 52

Aging

Answer 52

• general reduction in hormone production and response
  
  • decreased hGH, thyroid hormones (worn out thyroid)>but increased TRH and TSH (no negative feedback)
  • adrenal cortex becomes fibrous (medulla usually unaffected)> decrease cortex hormones
  • pancreas>releases insulin more slowly (glucose receptors less sensitive)
  • gonads
    
    • ovaries> decreased estrogen>osteoporosis, hyperlipidemia, atherosclerosis, menopause
    • testes>decrease in size but still produce test.; sperm are decreased quality
• bone injury
  
  • increased PTH likely due to decreased dietary calcium
  • calcitriol and calcitonin levels reduced
    *