Physiology Flashcards
Efflux Potassium (facilitated diffusion)
Inside membrane less positive
Membrane potential towards “resting” (K+)
Descending phase
Repolarization
Influx Sodium (facilitated diffusion) Inside b/c more positive Ascending phase Impulse likely Na++ gates close Threshold occures (-55 & -50 mV)
Depolarization
Before action potential (AP) begins
Membrane polarized
-90mV membrane potential
Resting state
Permeable to Na+ ions
Inside of neuron b/c more positive
-90mV immediately neutralized
Depolarization
Occurs 10,000ths of a second
Na+ channels begin to close & K+ channels open wider
Rapid diffusion of K+ to outside
Re-establishes normal negative resting membrane potential
Repolarization Stage
What are these two gates called:
Outside of channel is Activation Gate
Inside of channel is Inactivation Gate
-70 to -50 activation gate flips all the way open, Na+ ions pour in. Inactivation gate closes more slowly.
Voltage-gated Sodium Channel
T/F: Inactivation gate will not re-open until membrane potential is at or nearly at “resting membrane potential” level
True
Synaptic Transmission: Neuron sending the signal
Presynaptic neuron
Synaptic Transmission: Neuron receiving the signal
Postsynaptic neuron
Chemical Synapse from axon to dendrite
MC synapse
Axodendritic
Synapse from axon to soma
Axosomatic
Synapse from axon to axon
Axoaxonic
Tunnels that connect cytosol of two cells allowing AP to be transmitted directly from one cell to another thru Electrical Synapses. (Free flow of ions)
Common: Visceral (single unit), smooth & cardiac cells, embryo & CNS
Gap Junctions
Synapses where membranes are close together but do not touch; they require voltage-gated ion channels to transfer the AP
Chemical synapses
Separation b/t Axon Terminal of Presynaptic neuron & Dendrite of Postsynaptic neuron (therefore need NT to transfer AP)
- Takes 0.5 m/sec
- Only synaptic end-bulbs of presynaptic neurons release NT
Synaptic cleft
Synaptic delay
One way transmission
Excitatory NT’s
Norepinephrine
Glutamate
Nitric Oxide
NT for Brain stem, hypothalamus, etc
Norepinephrine
NT for CNS, cerebral cortex
Glutamate
NT for Brain (quickly diffuses)
nitric oxide
Inhibitory NT’s
Acetylcholine (ACH) Dopamine Glycine GABA Serotonin
NT for Motor cortex
ACH
NT for Substantia nigra (parkinsons)
Dopamine
NT for Spinal cord
Glycine
NT for Spinal cord, cerebellum, basal ganglia
GABA
NT for Brain stem
Serotonin
1,000 to 10,000 synapses received (CNS)
Summation
Buildup of NT’s released to several presynaptic bulbs
Spatial summation
NT released to single presynaptic bulb which fires 2x or more
Temporal summation
Demyelinating diseases
MS
PLS (posterolateral sclerosis)
ALS (lou gherigs disease)
Myelin is made of…
Fat
Terminal bulbs where NT stored
Telodenria
Regularly spaced patches of membrane on axon with no insulation whose purpose is to boost signal & prevent decay of AP
Nodes of Ranvier
(saltatory conduction)
“hopping”
Free nerve endings
pain, tickle, itch & temperature
Pain - Nociceptors
Location of greatest number of pain nociceptors?
Tip of tongue
Lips
Genitalia
Finger tips
Location of least number of pain - nociceptors
Upper arm
Buttock
Trunk
Algesia = ?
Pain
Mechanoreceptor: Pressure (encapsulated)
End bulbs of Krause
Mechanoreceptors: temperature perception & pressure (encapsulated & multi-branched)
2-5 degrees of perception
Corpuscles of Ruffini
Receptor: General touch (ant spinothalamic tract) & Hair follicles
NOT encapsulated
Merkel’s Disc
When Merkel’s disc is grouped together it’s termed….
Iggo Dome Receptor
Receptor: Fine touch (dorsal columns), Located on non-hairy skin
(encapsulated)
Meissner’s Corpuscles
Receptor: Pressure, Vibration (encapsulated)
“Phasic receptor”
“Quick adaptor”
Pacinian Corpuscles
Proprioception Receptors:
- Stretch (dynamic & static ONLY in skeletal muscle)
- Load or Weight
- Prevents excessive tension in a muscle
Muscle Spindles
Golgi Tendon Organs
Golgi Tendon Reflex
ANS: Blood Vessels/Skin
- sympathetic?
- parasympathetic?
S: Vasoconstricts - shunts blood via vasomotor control to proximal limbs & lungs
PS: Little or no effect
ANS: Muscle
S: No
PS: yes
ANS: Heart
S?
PS?
S: Tachycardia (increases rate)
PS: Bradycardia (decreases rate)
ANS: Lung/Bronchi
S?
PS?
S: Deep breaths / Dilates bronchi
PS: Shallow breaths / Constrict bronchi
ANS: Eyes / Pupils
S: Dilates (Medriasis)
PS: Constricts (Meiosis)
ANS: GI / Peristalsis / Colon
S: Decreases secretions & digestion
PS: Increases secretions & bowel movement activity
ANS: Receptors
S: Adrenergic
PS: Cholinergic
ANS: NT - Preganglionic / Postganglionic
S: Pre - ACH
Post - Epi/Norepi
PS: ACH
Locus ceruleus nucleus (pons) “adrenal glands of the brain” NT?
Epinephrine
Quick Quiz:
- Influx of sodium
- Efflux of sodium
- Period after firing when no AP possible (can’t be stim again)
- AP available w/ increase potential by K+
- Many synapses in single cell
- Rapid succession of AP w/ few synapses
Depolarization Repolarization Absolute Refractory Period (hyperpolarization) Relative Refractory Period Spatial Summation Temporal Summation
Binds to & blocks glycine receptors causing massive tetanic contractions; diaphragm cannot “relax”, can’t breath, DIE!
Strychnine (poisoning)
Inhibitory neurons in spinal cord that releases glycine & prevents excessive muscular contraction
Renshaw cells
Cerebral Sensory Areas: Somatosensory
Postcentral Gyrus (parietal lobe)
Cerebral Sensory Areas: Visual
Occipital lobe, Striate cortex, Calcarine fissure
Cerebral Sensory Areas: Auditory
Superior Temporal lobe, Heschl’s gyrus
Cerebral Sensory Areas: Gustatory
Base of postcentral gyrus
Cerebral Sensory Areas: Olfactory
Medial temporal lobe
Cerebral Sensory Areas: Wernicke’s area
“Receptive” portion of language (Superior Temporal Lobe)
Cerebral MOTOR Areas:
- Precentral gyrus (frontal lobe)
Motor
Cerebral MOTOR Areas:
- Skilled movements (anterior to motor cortex)
Premotor
Cerebral MOTOR Areas:
- “Expressive” portion of language (inf post frontal lobe)
Broca’s area
What is responsible for coordination of muscle contractions? Clinical: - Staccato or slurred speech - Intention tremor - Nystagmus
Cerebellum
Multiple Sclerosis symptoms
Main relay between cortex & spinal cord
“Crude sensation”
Thalamus
Controls ANS & Endocrine system
Controls body temperature (median eminance), food intake, thirst
Functions in rage & aggression
Helps maintain waking state & sleep
Releases Somatostatin - decrease secretion insulin & glucagon
Hypothalamus
Emotional aspects of behavior related to survival
Includes: Fornix, Hippocampus, Cingulate Gyrus, Amygdala, Parahippocampal Gyrus & parts of the Thalamus
Limbic System
Part of midbrain the coordinates eyeball movement in response to visual stimuli
Superior colliculi
Part of midbrain that coordinates head & trunk auditory stimuli (CN III, IV)
Inferior Colliculus
Pneumotaxic & apneustic
Breathing origin of CN V, VI, VII, VIII
Pons
Reticular formation (with diencephalon, pons, midbrain) that functions in consciousness & arousal.
Vital reflex centers regulate heartbeat, breathing & BV diameter.
Coordinates swallowing, vomiting, coughing, sneezing & hicups.
Vestibular Nuceli help maintain equilibrium
Origin: CN VIII, IX, X, XI, XII
Medulla
Dark spots, Aging, Product Oxidation
Lipofuscin
Cardiovascular Physiology:
- Average bpm?
- mL of blood per beat?
- Heart is behind…?
- Normal BP?
75 bpm
70-80mL of blood per beat
Heart behind 2nd - 5th ribs
120/80 normal BP
Pacemaker of the heart?
Innvervated by….?
How does it affect heart rate?
Sinus (SA) Node
N: Vagus Nerve (CN X)
Decreases heart rate
If SA Node dies, what node takes over?
AV Node
SA Node prevents _____.
Tetany
Parasympathetic innervation to 90% of the body
Vagus (CN X)
List the pathway of blood thru the heart.
Superior Vena Cava — Inferior Vena Cava — Right Atrium — Tricuspid Valve — Right Ventricle — Pulmonary Valve — Pulmonary Artery — Lungs
(Deoxygenated blood)
Lung capillaries — Pulmonary Vein — Left Atrium — Mitral Valve — Left Ventricle — Aorta — Brain, Heart, Body
(oxygenated blood)
Nodes & bpm:
- SA Node
- AV Node
- Bundle of HIS
- Purkinje Fibers
- Bundle Branches
SA: 60-80 bpm AV: 40-60 bpm HIS: 20-40 bpm Pur: 0-20 bpm BB: n/a
Echocardiogram (ECG):
- P = phase?
- ST = time?
- QRS = phase?
- T = phase?
P = Atrial depolarization ST = .04 to .06 seconds QRS = Ventricle depolarization & Atrial repolarization (obscured) T = Ventricle repolarization
Describe how the body maintains the resting state of the heart
“PUMP-K-IN”
- ATP driven
- Na+ out
- K+ in
- 3 Na+ for every 2 K+
Depolarization = \_\_\_\_\_ Repolarization = \_\_\_\_\_
D = Work R = Rest
Valve Sounds:
Closing of Mitral & Tricuspid (AV Valves)
S1 sound
Valve Sounds:
Closing of Aortic & Pulmonic valves (semilunar)
S2 sounds
What tests would you do for the following:
- Heart
- Muscle
- Brain
H: EKG, ECG
M: EMG
B: EEG
Contraction of heart
Systole
Period of time when heart refills with blood after systole (contraction); period during which ventricle or atrium is relaxing (dilation)
Diastole
Diastole murmurs are the most clinically significant:
name them
Aortic Regurgitation
Mitral Stenosis
Pulmonic Regurgitation
Tricuspid Stenosis
Mitral Valve regurgitation is loudest at….
Left Ventricle
MC valvular heart disease?
Mitral Valve Regurgitation
Force exerted by fluid against a wall
Hydrostatic pressure
Pressure created by plasma proteins unable to move through the capillary membrane?
Osmotic Pressure
Stroke volume increases in response to increase in volume of blood filling the heart
Frank Starlings Law
aka Maestrini heart’s law
Muscle will increase in size when used
Davis’ Law
Inversely proportional relationship between absolute pressure & volume of gas, if temp is kept constant within a closed system
Boyle’s Law
What is the algebraic equation for heart?
pV = k
p - pressure of system
V - denotes volume of gas
k - constant of pressure & volume of system
Precursor platelets are…
Megakaryocytes
MC type of blood cell whose principle means is delivering oxygen to tissues thru circulatory system.
RBC “Erythrocytes”
Cytoplasm of RBC is rich in _____ which binds oxygen & is responsible for blood color
Hemaglobin (15g/100ml) - iron
Production of RBCs:
- Embryo
- Fetus
- Adult
E: Yolk Sac
F: Liver, Spleen, Lymph, Bone Marrow
A: Membranous Bone Marrow
Genesis of RBC
Hemocytoblast – Normoblast – Reticulocyte (1% blood) – Erythrocyte (99% blood - no nucleus)
“HNRE”
Where is Erythropoietin made & what does it stimulate?
Made in Kidney
Stimulates RBC production
What is the life expectancy of RBC & where is it recycled?
120 days
Recycled by macrophages in Spleen (heme is saved)
CO2 is transported in blood by …
Plasma Bicarbonate
Iron:
- transport?
- storage?
- absorption?
T: Transferrin (Fe +3)
S: Ferritin (Fe +3 & apoferritin)
A: Fe+2 (requires vitamin C to remain reduced)
White blood cells are called _____
Leukocytes
White blood cells consist of …
Neutrophils (60%) Lymphocytes (30%) Monocytes (8%) Eosinophils (3%) Basophils (0%)
“Never Let My Engine Blow 60-30-8-3-0”