Phys II Flashcards
Contents of the telencephalon
Basal ganglia (nuclei); olfactory lobes and nerves; cerebral hemispheres
Contents of Diencephalon
Epi thalamus; thalamus; hypothalamus and infundibulum
Contents of mesencephalon
Cerebral aquaduct; superior and inferior colliculi; tegmentum
Contents of metencephalon
Cerebellum and pons
Contents of myelencephalon
Medulla oblongata; posterior choroid plexus
Primary motor areas
Direct connections w/ specific muscles
Primary sensory areas
Detect specific sensations
Secondary motor areas
Provide patterns of motor activity
Secondary sensory areas
Analyze meanings of specific sensory signals
Characteristics of tonic receptors
Slow adapting; detect continuous stimulus strength; transmit impulses as long as stimulus is present
Types of tonic receptors
Muscle spindles; Golgi tendon organs; macula and vestibular receptors; baroreceptors; chemoreceptors
What are the neurons that make up the 3-neuron ascending pathways?
Primary sensory neurons: from external receptors; travel through dorsal roots of spinal cord
Secondary neurons: make up tracts in spinal cord and brainstem; neurons typically terminate in thalamus
Tertiary neurons: from thalamus to primary sensory cortex; travel through internal capsule
Anterolateral Spinothalamic Tract
Carries pain and temp; primary fibers ascend or descend 1-2 spinal cord segments before synapses w/ secondary fibers; secondary axons decussate through anterior gray and white commissures; secondary axons make up the lateral Spinothalamic tract traveling in the lateral column of the spinal cord
Medial lemniscuc system
Aka posterior column system; carries sensations for 2-point sensation (fine touch), pressure and vibration; primary fibers ascend entire length of spinal cord and synapse w/ secondary neurons in medulla - fasciculus gracilis and fasciculus cuneatus
Group 1a (type Aalpha) fibers:
Fibers from annulospiral ending of muscle spindles
Group Ib (Aalpha) fibers:
Fibers form Golgi tendon organs
Group II (Abeta, gamma) fibers:
From cutaneous tactile receptor and flower-spray
Group III (Asigma) Fibers:
Carry temp, crude touch, and pricking pain
Group IV (Type C) Fibers:
Carry slow chronic pain, itch, temp, and crude touch
Review Rhodopsin-retinal visual cycle
Slide 9
W Ganglion Cells
Make up about 40% of all ganglion cells; small; transmit signals 8m/sec.; receive most of their excitation from rods transmitted by way of small bipolar cells and amacrine cells; they have broad fields in the peripheral retinal b/c their dendrites spread widely in the inner plexi form layer
X Ganlgion Cells
Make up about 55% of all ganglion cells; medium diameter; transmit signal 14 m/sec; they have small fields - signals represent discrete retinal locations; every X Ganlgion cell receives at input from at least one cone cell; therefore probably responsible for all color vision
Y ganglion cells
Make up about 5% of all ganglion cells; large; transmit signals 50m/sec or faster; respond to rapid changes in visual image; presumably apprise the CNS almost instantaneously when a new visual event occurs anywhere in the field w/o great accuracy w/ respect to location of field `
Hair cells
100 sterorcelia on apical border; longer on the side farther from modiolus; when cilia are bent, a mechanical transduction is created that opens K channels resulting in depolarization of hair cell membrane;
High K concentration in the __________ is related to the resting potential w/I hair cells and generation of action potential
Endolymph
What is the most common cause of congenital deafness?
Inability of the Syria vascular is to conduct K ions into the external fluid
Muscle spindle
3-12 intrafusal fibers - innervated by small gamma motor neurons***; central region has no contractile fibers; functions as a sensory receptor - sensory fibers originate from central region, stretching of central region of intrafusal fiber stimulates sensory fibers; detects changes in muscle length
Upper motor nuerons
Originate in motor corticies; most decussate in pyramids and form the lateral corticospinal tracts; others decussate near synapse w/ lower motor neurons and form anterior corticospinal tracts; most synapse w/ association neurons in spinal cord central gray
The pyramidal system consists of what 2 tracts?
Corticospinal and corticobulbar tracts
Dentate nuclei, emboli form nuclei, globose nuclei:
Lesions in these nuclei –> extreme ataxia; these fibers project to the red nucleus; related to limb musculature and fine manipulative movement
Fastigial nuclei
Lesions –> trunk ataxia; fibers project to reticular formation and vestibular nuclei; related to postural actiity and limb movements via reticulospinal and vestibulospinal tracts
Cells in cerebellar cortex
Basket and stellate cells provide lateral inhibition on adjacent purkinje cells to provide damping
Purkinje cells
Extensive dendritic branching; receive input from parallel fibers (20,000 synapses b/w parallel fibers and 1 purkinje cell); project to intracerebellar nuclei (-); ONLY output from cortex **
Vestibulocerebellum:
Consists of floccoulonodular lobes and vermis; loss of floccoulonodular lobes –> extreme disturbance of equilibrium and postural movements
Spino cerebellum
Consists mostly of vermis and intermediate zone; receives - info from motor correct and red nucleus telling cerebellum intended sequential plan of movement for next few fractions of seconds and feedback info from periphery telling cerebellum what actual movement resul
Cerebrocerebellum
Consists of lateral parts of hemispheres; mostly associated w/ pre motor and primary and association somatosensory areas of cerebral cortex; involved in coordination of skilled movement and speech; plans as much as tenth of second in advance of actual movements
The primary motor area for shivering is the ?
Dorsi medial portion of the posterior hypothalamus
What is one of the best known stimuli for increasing the rate of thyroid releasing hormone secretion?
Cold
What is the critical body core temp?
37.1 C (98.8 F)
How does the core temp relate to heat loss and heat production?
Heat loss is greater and temp above core temp and heat production is greater and temps below core temp
What is the set-point of the temp control mechanism?
Level at which sweating begins or shivering begins in order to return to critical core body temp
What are the physiological mechanisms that a letter the critical set point?
Primarily skin temp changes
Slow waves are or are not action potentials?
Are NOT
Slow waves
Slow undulating changes in the resting membrane potential; intensity varies b/w 5-15 mV; frequency ranges from 3-12 per min; may be caused by complex interaction amount the smooth muscle cells and intertitial cells of Cajal (smooth muscle cells electrical pacemakers) - cells of Cajal undergo cyclic changes that periodically open and produce inward (pacemaker) currents that may generate slow wave activity; slow waves excite the appearance of intermittent spike potentials which excite muscle contraction
Interneurons of my enteric plexus
Utilize serotonin as a neutrotransmitter; individuals on serotonin reputable inhibitors may experience decreased GI motility
Spike potentials
True APs; occur automatically when resting membrane potential of GI smooth muscle becomes more positive than -40 mV; the higher the slow wave potential, the greater the frequency of spike potential; last longer than typical AP; responsible for opening Ca channels and Na channels; channels open slowly and close rapidly
Reflexes from the gut to the prevertebral sympathetic ganglia and then back to GI tract:
Transmit signals long distance to other ares of the gut tract; cause evacuation of the colon (gastrocolic reflex); inhibit stomach motility and secretion (enterogastric reflex); empty ileal contents into the colon (colonoileal reflex)
Parietal cells secrete what?
HCl
Review diagram on how parietal cells secrete HCl
Slide 26-27
CCK
Release is stimulated by presence of food in upper intestine; secreted by duodenal and upper jejunum mucosal cells; results in dramatic increase in secretion of pancreatic enzymes; stimulates pancreatic bicarb secretion; inhibits gastric emptying; inhibits appetite
Secretin
Release is stimulated by presence of acidic foods in upper intestine; secreted by duodenal and upper jejune like mucosal cells; stimulates release of large amounts of Na Bicarb; stimulates bicarb secretion; inhibits gastric acid secretion
Factors that influence metabolic rate
Arousal vs. sleeping; skeletal muscle; age; thyroid activity; testosterone; growth hormone; fever; sleep; malnutrition;
**note that cold is one of the best known stimuli for increasing the rate of thyroid stimulating hormone
Liver has ______ blood flow and. ______ vascular resistance
High ; low
27% of resting cardiac output flows into liver each min.
Explain why liver can store blood in times of excess and supply blood in times of dismissed vol.
Normal vol. of liver = 450 ml (10% of body’s blood vol); high pressure in right atrium –> back pressure on liver –> increased blood vol in liver up to 1.5 L - may occur during cardiac failure w/ peripheral congestion
VLDLS:
High concentrations of TAGs and moderate amounts of cholesterol and phospholipids; transport lipids mainly from liver to adipose tissue
LDLs
High concentration of cholesterol and moderate concentration of phospholipids
HDLs
High concentration of proteins and low concentration of cholesterol and FAs
Review Bilirubin formation
Slide 33
TAGs as an energy source - FAs are converted to Acetyl-CoA in the mitochondria :
= beta oxidation; carnitine is used as a carrier molecule into mito; Acetyl-CoA enters the citric acid cycle by binding to oxaloacetic acid; hydrogens enter the chemiosmotic oxidative system
What 2 steps of the ornithine cycle occur in the mitochondria?
Ammonia + CO2 –> carbamoyl phosphate
Carbamoyl phosphate + ornithine –> citruline
Iodine metabolism
Thyroid cells also secrete thyroglobulin into follicle - each thyroglobulin molecule has about 70 tyrosine aas which bind iodine to from thyroid hormones; iodide ions are converted to an oxidized form of iodine - either I3 or nascent iodine which both can bind directly to tyrosine; major hormonal product is thyroxine (T4): formed when 2 molecules of diiodotyrosine are joined together or 1 monoiodotyrosine may combine w/ 1 diiodotyrosine to form T3
PTH effects of bone in causes absorption of Ca and phosphate
The cell membranes of both osteoblasts and osteocytes have receptor proteins for PTH; PTH can activate Ca pump and cause rapid removal of Ca phosphate salts from those amorphous bone crystals that lie near cells
PTH effect on renal Ca reabsorption
Administration of PTH causes rapid loss of phosphate in the urine: due to effect of hormone to diminish proximal tubular reabsorbtion of phosphate ions
PTH also increase renal tubular reabsorbtion of Ca and diminishes phosphate reabsorbtion
ANS pathways consist of 2 neurons in sequence:
Preganglionic neuron: cell bodies located w/I CNS; myelinated axons; Ach is neurotransmitter
Postganglionic: cell bodies in peripheral ganglia; non myelinated axons; NT is Ach in parasympathetics and norepinephrine in sympathetic system
Physiologic anatomy of parasympathetic system
About 75% of all parasympathetic fibers are in the Vagus N. (CN 10); most preganglionic fibers pass all the way to the organ that is innervated; postganglionic parasympathetic fibers: located in wall of organ and use Ach as NT
Review interaction of follicular cells in estrogen production and hormones
Slides 41 and 42
Testosterone is formed by the ?
Intertitial cells of Leydig: cells are numerous in newborn males and adult males after puberty - almost nonexistent in testes during childhood
After testosterone secretion:
97% is loosely bound w/ albumin or tightly bound w/ beta globulin; circulates in blood for 30 min. - several hours; transferred to tissues or degraded to inactive products that are subsequently secreted
Major functions of placenta
PO2 of mother: 50 mm Hg
PO2 of fetus: 30 mm Hg
Reasons why adequate oxygenation can occur w/ such a low pressure gradient (20 mm Hg): Fetal Hb; Fetal blood Hb concentration is about 50% greater than maternal; Bohr effect
