Final Exam (Endocrine System, Stress Response, & Semi-Cumulative Topics) Flashcards
what is the classic definition of a hormone
chemical substance produced in a specialized gland (endocrine gland)
where are hormones released
the bloodstream
where are hormones transported to
(sometimes) distant target cells/tissues to elicit (produce) a response
How do hormone pathways and interactions work
in negative feedback loops
(sometimes positive - like labor)
Where are hormone receptors located
protein molecules located either;
-on cell membrane
-inside the cell (cytoplasm or nucleus)
What is the job of hormone receptors
bind specific hormones in specific target tissues to produce a biological effect (usually through protein modification)
*Key factor that determines if a cell will respond to a hormone is if it has receptors for that hormone!
-Hormone MUST bind to its proper receptor to have an effect
How are hormones classified
based off of their structure
-amino acid OR
-lipid based
what are the types of hormones we discussed
Peptide hormones
Steroid hormones
Amines: Catecholamines, thyroid hormones
What is the structure of steroid hormones
lipid based
describe process of steroid hormone synthesis
-Cholesterol (a lipid) is precursor to ALL steroid hormones
-conversion of cholesterol to pregnenolone via P450scc in mitochondria
-further conversion by additional enzymes (mostly in smooth ER)
How does testosterone (T) get to Estradiol (E2)
via aromatase enzyme
How are steroids transported through blood
via binding proteins because steroids are non-water-soluble
What kind of receptors do steroids have
intracellular receptors (in cytoplasm or nucleus)
Describe the process of peptide/protein hormone synthesis
-made up of Amino acids
-soluble in water, so they freely travel through blood w/o binding globulins
-stored in vesicles
-Synthesis is done via transcription & translation
what kind of receptors do peptide hormones have
cell membrane receptors
Describe cell membrane hormone receptors
result in fast response (seconds to minutes)
-used by peptide/protein and most amine hormones (like epinephrine)
Describe intracellular hormone receptors
result in slower response (~20-90 minutes)
-used by steroids and thyroid hormones
What are the classes of cell membrane receptors
-ligand-gated channel
-receptor enzyme
-g protein coupled receptor
-integrin
Describe how the G-protein coupled receptor works
- hormone binds to receptor
- GTP replaces GDP on Alpha subunit of G-protein
- Alpha subunit dissociates
- Alpha subunit activates adenylyl cyclase
- Adenylyl cyclase produces cAMP from ATP
- cAMP activates protein kinase A
- Protein Kinase A phosphorylates proteins inside cell
—–> leads to RESPONSE IN CELL
What specific receptor do many peptide hormones use
G-protein coupled receptor
Describe how intracellular receptors work
-steroid enters target cell by simple diffusion
-steroid binds to receptor
-activated steroid-receptor complex translocates to nucleus
——>binds to DNA & initiates gene transcription
——>Production of new proteins
—————> Leads to RESPONSE IN CELL
what receptor do steroids and thyroid hormones use
intracellular receptors
TRUE OR FALSE
-There is an important close relationship between the hypothalamus & pituitary
TRUE
what are Hypothalamic nuclei
clusters of neuron cell bodies that make up the hypothalamus
Describe the Hypothalamus-Pituitary complex
-Hypothalamus secretes hormones into capillary network: Hypophyseal portal system
-hormones carried to anterior pituitary
-Anterior Pituitary secretes different hormones in response
Describe the Hypothalamus’s interaction with the posterior pituitary
-axons from hypothalamic neurons extend into posterior pituitary
-same hormones produced in hypothalamus are secreted by posterior pituitary
Describe the anatomy of the anterior lobe of the pituitary gland
composed of epithelial or “true” endocrine tissue
Describe the anatomy of the posterior lobe of the pituitary gland
composed of neural tissue
what is the entire pituitary gland housed in
bony capsule in sphenoid bone known as Sella Turcica
What hormones are produced in the cell bodies of hypothalamic nuclei and secreted by the posterior pituitary
Oxytocin (OT)
Vasopressin (VP)
what kind of hormones are Oxytocin and Vasopressin
Neurohormones
what are the physiological roles of Oxytocin (OT)
-milk release by lactating women
-uterine contractions during labor (this is positive feedback related to hormones)
what are the behavioral roles of Oxytocin (OT)
-maternal behavior
-mating behavior
-social behavior
-sexual response
what are the physiological roles of Vasopressin (VP) A.K.A. Antidiuretic Hormone (ADH)
water balance
-VP induces water reabsorption at kidney tubules
Blood pressure regulation
-VP causes vasoconstriction (increased BP)
what are the behavioral roles of Vasopressin (VP) A.K.A. Antidiuretic Hormone (ADH)
Social behavior
-crystallization of social memory (allowing you to remember people you met a few days-years ago)
Which cells make up 2% of the total mass of the pancreas
Endocrine cells
What are the Islets of Langerhans
cell clusters in the pancreas
which cells make up 75% of the Islets of Langerhans and what do they secrete
Beta Cells
-secrete insulin (a peptide hormone)
which cells make up 20% of the Islets of Langerhans and what do they secrete
Alpha cells
-secrete glucagon (a peptide hormone)
which cells make up 4% of the Islets of Langerhans and what do they secrete
D cells
-secrete Somatostatin
which cells make up 1% of the Islets of Langerhans and what do they secrete
F Cells
-secrete pancreatic polypeptide
what occurs in the endocrine pancreas
glucose homeostasis
how does the endocrine pancreas maintain glucose homeostasis
when blood glucose is high:
-insulin released, induces target cells to take up glucose
———> blood glucose goes down
When blood glucose is low:
-Glucagon released, induces release of glucose from target cells
———>blood glucose levels go up
Describe Insulin
Produced from Beta cells of Islets of Langerhans
-needed for normal growth and development
-ONLY hormone that lowers blood glucose
-stimulus for secretion=increased glucose in blood
what does insulin act on and what response does it produce
liver, skeletal & cardiac muscle, and adipose tissue cells
-Enhance glucose uptake —–> lowers blood glucose levels
-induces glycogen synthesis, or protein & fat synthesis
what happens if insulin is absent
unregulated high blood glucose levels
what occurs due to inadequate insulin secretion, abnormal target cell responsiveness, or both
Diabetes Mellitus
How does insulin lower blood glucose
via glucose transport proteins (GLUTs)
how does insulin affect blood glucose via GLUT4s
-Insulin binding causes insertion of GLUT4s into plasma membrane
-Facilitated diffusion of glucose into cells
Where are GLUT4s found
GLUT4s present in striated muscle (cardiac & Skeletal), and adipose tissue
how does insulin affect blood glucose via GLUT2s
-not dependent on insulin, always present in plasma membrane
-insulin alters intracellular glucose levels, creating concentration gradient to facilitate glucose movement (in or out)
where are GLUT2s found
GLUT2s present in liver, pancreas, intestine, and kidneys
What is Diabetes Mellitus typically characterized by
the inability to lower blood glucose levels
what characterizes Type I diabetes
There is no insulin production from the pancreas
what is the cause of Type I Diabetes
Autoimmune destruction of Beta cells, resulting in no insulin production
What is the treatment for Type I Diabetes
Insulin replacement (injection or pump)
What characterizes Type II Diabetes
Receptors for insulin are non-functional (insulin resistance)
-initial upregulation of insulin secretion followed by reduction of insulin secretion
what is the cause of Type II Diabetes
Multifactorial
-Biggest Risk factors=Genetics (family history), ethnicity, & stress
-Other=inactivity, age, & diet
what is the treatment for Type II Diabetes
Dietary management
Physical exercise
medication to lower blood glucose
why is physical exercise a possible treatment option for Type II Diabetes
Contracting striated muscle leads to GLUT4 expression & membrane insertion, and glucose uptake independent of insulin
what medication is commonly used to treat Type II Diabetes
Metformin
-reduces hepatic gluconeogenesis and enhances insulin sensitivity
what characterizes gestational diabetes
Insulin resistance or reduction of insulin production during pregnancy
what is the cause of gestational diabetes
unknown/many
what are treatment options for gestational diabetes
dietary management
physical exercise
insulin
What produces Glucagon
Produced by Alpha cells of Islets of Langerhans of pancreas
What are Glucagon’s target tissues
liver and adipose tissue
what does glucagon induce
glyconeogenesis, gluconeogenesis, and lipolysis
what does Glucagon do
Increases blood glucose
-Antagonistic effect to insulin
define stressor
anything that disrupts homeostasis (internal or external)
define stress response
physiological & behavioral responses that attempt to reestablish homeostasis
what is general adaptation syndrome
3 stage process of responding to stress
who founded general adaptation syndrome
Hans Selye (1907 - 1982)
what are the 3 stages of general adaptation syndrome
- alarm reaction stage
- resistance stage
- exhaustion stage
Where are the adrenal glands located
sit on top of the kidneys
Describe the Adrenal medulla
the inner portion of adrenal glands
-nervous tissue origin (neuroendocrine)
what does the adrenal medulla secrete
catecholamines
-Norepinephrine
-epinephrine
Describe the adrenal cortex
the outer portion of adrenal glands
-made of epithelial tissue (“true” endocrine tissue)
what does the adrenal cortex secrete
glucocorticoids (steroids)
Describe the Neuroendocrinology of the stress response
Integration of 2 systems
-sympathetic branch of ANS
(releases catecholamines)
-HPA Axis
(releases Glucocorticoids)
what are the additional hormones secreted during stress response
beta-endorphins - pain suppression
vasopressin - increases blood pressure
prolactin - unclear function
Describe the Alarm reaction stage of general adaptation syndrome
Activated within seconds of appearance of stressor
-catecholamine (epinephrine & norepinephrine) release from adrenal medulla
*fast acting “fight-or-flight” response triggered
what are the functions of catecholamines
Variety of effects
Increases:
-alertness, memory, O2 intake, glucose availability, blood flow to muscles, heart rate, blood pressure
Inhibits:
-digestion, pain perception
Describe the Resistance stage of general adaptation syndrome
Activated within minutes to hours, if stressor continues
-activation of hypothalamic-pituitary-adrenal (HPA) axis
Steps of Hypothalamic-Pituitary-Adrenal (HPA) Axis
-Stressor causes hypothalamus to release corticotropin releasing hormone (CRH)
-this causes Anterior pituitary to release adrenocorticotropic hormone (ACTH)
-this causes adrenal cortex to release glucocorticoids (cortisol & corticosterone) to target tissues
-this causes blood glucose to increase
*this is negative feed back at hypothalamus and anterior pituitary
What are 2 specific glucocorticoids and what kind of hormones are they
corticosterone & cortisol
-these are metabolic hormones
Describe when corticosterone & cortisol are activated and how they are transported
Peak shortly after waking (“morning burst”)
-this provides energy for our day
Also elevate in response to stress
*Moved through blood via carrier corticosterone binding globulin (CBG)
what receptors do glucocorticoids bind to
intracellular receptors (mostly)
-they are steroids
what are the major effects of glucocorticoids
They are essential for life:
Major effect=increases blood glucose
-induction of gluconeogenesis in liver
-reduction of cellular glucose uptake
what are the additional effects of glucocorticoids
-Breakdown of proteins and fats
-suppress immune response, reproduction, & digestion
Route energy away from non-essential functions, and route energy to survival-based functions during entire stress response
Describe the exhaustion stage of general adaptation syndrome
occurs if stressor continues for days, weeks, months, or years
-there is continued secretion of epinephrine, norepinephrine, and cortisol
which stages of general adaptation syndrome are categorized as acute stress
alarm reaction stage
resistance stage
which stage of general adaptation syndrome is categorized as chronic stress
exhaustion stage
define allostasis
physiological process of returning the body to homeostasis
define allostatic load
body “wear and tear” overtime due to costs of allostasis
define allostatic overload
costs outweigh available energy
-results in stress-related pathologies
examples of physical stress
baboons fighting
cheetah chasing its food
examples of psychosocial stress
war
skydiving
stressful job
exams at school
what chronic stress pathology does the acute stress response of increased energy use cause
fatigue
myopathy (muscle fatigue)
what chronic stress pathology does the acute stress response of increased cardiac output cause
hypertension (high BP)
what chronic stress pathology does the acute stress response of inhibited digestion cause
ulcers
what chronic stress pathology does the acute stress response of inhibited reproduction cause
infertility
what chronic stress pathology does the acute stress response of immunosuppression cause
loss of disease resistance
what chronic stress pathology does the acute stress response of enhanced cognition cause
neural degeneration
What is the anatomical body position?
position in which feet are pointed forward, body is standing up straight, and palms are facing out
What are the non-standing body positions?
supine and prone
Define supine
body position in which someone is laying on their back, face up
Define prone
body position in which someone is laying on their stomach, face down
What are directional terms?
They usually come in pairs and compare structures
How are proximal and distal used to compare structures?
used to compare linear structures such as the arms or legs
Define proximal
closer to the attachment point to the body
(Ex. the elbow is proximal to the wrist)
Define distal
farther from the attachment point to the body
(Ex. elbow is distal to the shoulder)
How are superior and inferior used to compare structures?
They are NOT used when referring to arms or legs because this is not as accurate in all the body positions
Define superior
above
(Ex. The head is superior to the chest)
Define inferior
below
(Ex. the nose is inferior to the eyes)
Define medial
closer to the midline (middle) of the body
(Ex. The spine is medial to the ribcage)
Define lateral
Away from the midline (middle) of the body, closer to the sides of the body
(Ex. The lungs are lateral to the heart)
Define Anterior
towards the front of the body
(Ex. the eyes are anterior to the butt)
Define posterior
towards the back of the body
(Ex. the Achilles tendon is posterior to the nose)
Define superficial
closer to the surface of the body
(Ex. the skin is superficial to the bones)
Define deep
toward the core (center) of the body
(Ex. The bones are deep to the skin)
Draw a diagram of the 9 square abdominal divisions and label them
Look at diagram
Define Homeostasis
Homeo=similar
Stasis=period or state of inactivity or equilibrium
Maintenance of relatively constant internal body conditions - despite changes in the external environment - through activity of regulatory mechanisms.
(A.K.A. Dynamic Equilibrium in which body conditions are maintained within narrow limits)
What are positive feedback loops?
Rare, continued “vicious” cycle until ended by a major event
What is the goal of positive feedback loops?
increased stimulus, continual shift away from homeostasis
What are some examples of positive feedback loops?
Blood clotting, ovulation, labor during childbirth
What are negative feedback loops?
Most common type of feedback, responsible for almost all physiological regulation
What is the goal of negative feedback loops?
Reduce stimulus to return body to homeostasis
What are examples of negative feedback loops?
Blood glucose regulation, temperature regulation
What are the strata of the epidermis?
(Deep to Superficial)
1. Stratum Basale
2. Stratum Spinosum
3. Stratum Granulosum
4. Stratum Lucidum
5. Stratum Corneum
Describe the Stratum Basale
deepest layer of epidermis anchored to BM. Here keratinocyte stem cells divide via mitosis about every 19 days
Describe the Stratum Spinosum
2nd strata of epidermis where keratin a lamellar bodies filled with lipids accumulate in cells
Describe the Stratum Granulosum
3rd strata of epidermis where cells become diamond-shaped. Granules with the protein keratohyalin accumulate and lamellar bodies release their lipids. Cells die here.
Describe the Stratum Lucidum
4th strata of the epidermis where keratohyalin is dispersed around keratin fibers and cells flatten and overlap
Describe Stratum Corneum
5th and most superficial strata of the epidermis containing dead and overlapping squamous cells. Cornified cells (cells with “hard” protective layer of keratin) regularly slough off.
What is common pathology in integumentary system
burns
Degree refers to what of a burn
depth
what combines %BSA & depth of burns
burn severity
Define first-degree burn
only epidermis is affected
some pain, redness, swelling
fairly common
Define second-degree burn
damage to epidermis & dermis
these vary b/c dermis is thick
can be red, tan, or white (if deep)
can scar if deep enough
Define third-degree burn
epidermis and dermis completely destroyed
deeper tissues may be involved (like hypodermis)
sensory structures destroyed (affects ability to feel)
tan or brown color, leathery look
skin grafts often necessary
Define major burn
3rd degree burn covers over 10% BSA OR
2nd degree burn covers over 25% BSA OR
Burns to hands, face, genitals, or anal region
Define moderate burn
3rd degree burn covers 2-10% BSA OR
2nd degree burn covers 15-25% BSA
Define minor burn
3rd degree burn covers less than 2% BSA OR
2nd degree burn covers less than 15% BSA
Bone matrix composition
organic portion: collagen fibers (provides flexible strength)
Inorganic portion: hydroxyapatite - CaPO4 crystals (provides weight bearing strength
Long bone structures
Diaphysis:
-shaft of long bone
-mostly compact bone
Epiphyses:
-ends of long bone
-mostly cancellous bone
Epiphyseal plates:
-near epiphyses
-site of bone growth
-becomes epiphyseal line when bone growth stops
Medullary Cavity:
-hollow center in shaft
-contains marrows (red marrow during childhood, converts to yellow as we age)
Periosteum:
-Tissue membrane on outer surface of bone
-Outer layer - Dense irregular CT, continues with tendon
-Inner Layer - Bone Cells
Endosteum:
-lines all internal spaces including spaces in cancellous bone
What are the 3 types of muscles?
Skeletal muscle, smooth muscle, cardiac muscle
What are the functions of skeletal muscle?
locomotion (physical movement), posture, respiration
describe Skeletal muscle
voluntary (stimulated by motor neuron)
striated
What are the functions of smooth muscle?
contraction of hollow organs, vasoconstriction, vasodilation
describe smooth muscle
most widely distributed muscle type (in hollow organs & blood vessels)
involuntary (enteric and autonomic nervous system regulation - not controlled consciously)
Some are autorhythmic (initiate contraction w/o external nervous stimulation - muscles can self-contract)
what are the functions of cardiac muscle?
contraction of heart chambers
describe cardiac muscle
only found in heart
involuntary (regulated by autonomic nervous system)
Autorhythmic
striated
What is an action potential (AP)
temporary reversal of voltage (charge) inside cell —> voltage within cell becomes temporarily positive
“signal firing”
What are the stages of an action potential
- Resting Membrane Potential
-no ion channels open
Stimulus
-some Na+ channels open
-Na+ starts to move into cell (start of depolarization)
- Depolarization (2nd part)
-Voltage-gated Na+ channels are open
-Na+ rushes into cell - Repolarization
-Na+ channels close
-voltage-gated K+ channels open
-K+ rushes out of cell - Hyperpolarization
-“undershoot”
-excess K+ moving out of cell - Back to resting membrane potential
describe what occurs at a neuromuscular junction
- Action potential arrives at axon terminal
- Voltage-gated calcium (Ca++) channels open
-Ca++ rushes IN to axon terminal - Calcium ions (Ca++) triggers vesicles to release acetylcholine (Ach) into synaptic cleft
- Acetylcholine (Ach) diffuses across synaptic cleft
- Acetylcholine (Ach) binds to receptors on muscle fiber
- Na+ (sodium) channels open
-Na+ moves into muscle fiber
-triggers action potential (AP) in muscle fiber
Describe the process of neurotransmitter release to muscle contraction
- Acetylcholine secretion from motor neuron, Ach binds to receptors on muscle fiber (detailed steps at neuromuscular junction)
- Increased influx of sodium ions (Na+) into muscle fiber —> triggers muscular action potential
- Propagation of action potential across muscle fiber
- Depolarization of membrane and release of calcium ions (Ca++) from sarcoplasmic Reticulum (SR)
-due to: travelling of action potential into the inside of the fiber (T-tubules) - Cross-bridge formation & sliding filaments (or muscle contractions)
-due to: Ca++ binding to troponin
-troponin-tropomyosin complex moves out of the way, revealing active (binding) sites for myosin to bind on actin
6.Calcium ions (Ca++) goes back into sarcoplasmic reticulum (SR)
-restoration of filaments to original positions
How many major regions exist in the adult brain
4
what are the 4 major regions of the adult brain
- Cerebrum
- Diencephalon
- Brainstem
- Cerebellum
what does each region of the brain contain
nuclei
-clusters of neuron cell bodies in the Central Nervous System (CNS)
what is the cerebrum responsible for
higher brain functions
what does the cerebrum contain
cerebral cortex - layer of gray matter surrounding cerebrum
left & right cerebral hemispheres - separated by longitudinal fissure
what are the cortical lobes of the brain
frontal lobe
prefrontal cortex
parietal lobe
occipital lobe
temporal lobe
what are the functions of the frontal lobe
-motor functions
-planning movements and executing movements
what are the functions of the prefrontal cortex
-most anterior portion of the frontal lobe
-associated with personality
-regulation of emotional behavior & mood
-motor decision making
what is the function of the parietal lobe
processing of somatic sensations from body
what is the function of the occipital lobe
visual processing
what are the functions of the temporal lobe
-auditory processing
-regions for memory formation
what are the special functions of the cerebral cortex
-speech
-memory
what makes up the diencephalon
-thalamus
-hypothalamus & pituitary
what is the function of the thalamus
relay between cerebrum and rest of nervous system
what is the function of the hypothalamus & pituitary
-homeostatic regulation
-signal for regulatory mechanisms
-endocrine function
what is the function of the cerebellum
balance and coordination
how does the cerebellum work
using the cerebellar comparator function
What is the sympathetic branch of the ANS responsible for
“fight-or-flight” response
-physical activity & stress
Ex. increase Heart Rate, blood pressure, respiration
what is the parasympathetic branch of the ANS responsible for
“Rest-and-digest” response
-slow functions like digestion
-Vagus nerve stimulation (Cranial Nerve X (10))
Ex. decrease heart rate, blood pressure, respiration
what do cholinergic neurons secrete
acetylcholine neurotransmitter
what do adrenergic neurons secrete
norepinephrine neurotransmitter
what neurotransmitter do cholinergic receptors bind to
acetylcholine
what are the 2 subtypes of cholinergic receptors
nicotinic receptors
muscarinic receptors
where are nicotinic receptors found
on all postganglionic neurons of the ANS
-both sympathetic and parasympathetic branches
where are muscarinic receptors found
on effectors of the parasympathetic branch of ANS
what neurotransmitter do adrenergic receptors bind to
norepinephrine and epinephrine
where are adrenergic receptors found
on effectors of the sympathetic branch of ANS
what are the 2 subtypes of adrenergic receptors
alpha adrenergic receptors
-respond more to norepinephrine than epinephrine
Beta adrenergic receptors
-respond equally to norepinephrine & epinephrine
What is accommodation when referring to vision
keeping objects in focus via lens changing shape (use of ciliary muscle)
Distant objects:
-ciliary muscles relax, there is ligament tension on lens —->flatter lens shape
Near objects:
-ciliary muscles contract, less ligament tension on lens —->rounder lens shape
*as we age, lose ability to accommodate lens for vision
