PSL300 - Term test 1 COMPLETE QUESTIONS AND CORRECT
DETAILED ANSWERS WITH RATIONALES (VERIFIED
ANSWERS) |ALREADY GRADED A+
where is CSF produced
- most is produced by choroid plexus lining ventricles (some produced in
brain capillaries)
- made of epithelial cells connected by tight junctions
- continuously produces CSFF to circulate cleansing mechanism
- dense network of capillaries ballooning out into ventricular wall so
everything must be transported
arachnoid villi
- about 1/2 CSF drains through these into venous system
- out pouching of arachnoid tissue, sticks out through dura matter into
venous sinus
,composition of CSF, where is it mostly found
- same osmolarity and [Na] as blood
- reduced K, Ca, Mg (similar to interstitial fluid)
- total vol-215mL (cranial 140 - 25ml ventricles, 115 subarachnoid; spinal -
75)
- most CSF is in subarachnoid space
- we make 550 ml per day, so cycle 3x
lumbar puncture (spinal tap)
collect sample of CSF for analysis
astrocytes (glycolysis)
- provide bridge between neurons and blood vessels with "end feet"
- efficient at glycolysis
- absorbs glucose from capillary, producing lactate as end-product,
lactate is substrate for ATP production
- remove neurotransmitters (since near synapse)
- will line up single file since following blood vessels
- regulate local blood flow
,regulation of local blood flow by astrocytes
glutamate in synapses triggers Ca release within astrocytes, Ca wave
travels through astrocyte and triggers PGE2 (prostaglandin) release at
end-foot
PGE2 causes vasodilation and increased blood flow
facilitated diffusion
- carrier protein aids movement of polar molecules (selective)
- down [] gradient
- number of transporters will eventually saturate
secondary active transport
molecule transported against [] gradient, without ATP
voltage sensing mechanism of voltage gated channels
S4 segment, positively charged, normally attracted downwards towards
negative inner membrane
(when membrane depolarizes, no longer attracted, and wing lifts up,
opening the pore)
, synthesis, release, transport in blood, examples of hydrophilic and
hydrophobic hormones
hydrophilic- made in advance and stored, release by exocytosis,
dissolved in blood, eg. peptide/protein hormones, catecholamines
hydrophobic - made on demand, released by diffusion, bound to carrier
proteins in blood, eg. steroid and thyroid hormones
peptide hormones
3 or more AA, synthesized like secreted proteins, short half life in plasma,
eg. insulin, hydrophilic so dissolved in plasma
disulfide bonds on proinsulin
regions with disulfide bonds can get off, forming insulin, and the
remaining C-peptide is a byproduct and can be used to indirectly
measure insulin release
DETAILED ANSWERS WITH RATIONALES (VERIFIED
ANSWERS) |ALREADY GRADED A+
where is CSF produced
- most is produced by choroid plexus lining ventricles (some produced in
brain capillaries)
- made of epithelial cells connected by tight junctions
- continuously produces CSFF to circulate cleansing mechanism
- dense network of capillaries ballooning out into ventricular wall so
everything must be transported
arachnoid villi
- about 1/2 CSF drains through these into venous system
- out pouching of arachnoid tissue, sticks out through dura matter into
venous sinus
,composition of CSF, where is it mostly found
- same osmolarity and [Na] as blood
- reduced K, Ca, Mg (similar to interstitial fluid)
- total vol-215mL (cranial 140 - 25ml ventricles, 115 subarachnoid; spinal -
75)
- most CSF is in subarachnoid space
- we make 550 ml per day, so cycle 3x
lumbar puncture (spinal tap)
collect sample of CSF for analysis
astrocytes (glycolysis)
- provide bridge between neurons and blood vessels with "end feet"
- efficient at glycolysis
- absorbs glucose from capillary, producing lactate as end-product,
lactate is substrate for ATP production
- remove neurotransmitters (since near synapse)
- will line up single file since following blood vessels
- regulate local blood flow
,regulation of local blood flow by astrocytes
glutamate in synapses triggers Ca release within astrocytes, Ca wave
travels through astrocyte and triggers PGE2 (prostaglandin) release at
end-foot
PGE2 causes vasodilation and increased blood flow
facilitated diffusion
- carrier protein aids movement of polar molecules (selective)
- down [] gradient
- number of transporters will eventually saturate
secondary active transport
molecule transported against [] gradient, without ATP
voltage sensing mechanism of voltage gated channels
S4 segment, positively charged, normally attracted downwards towards
negative inner membrane
(when membrane depolarizes, no longer attracted, and wing lifts up,
opening the pore)
, synthesis, release, transport in blood, examples of hydrophilic and
hydrophobic hormones
hydrophilic- made in advance and stored, release by exocytosis,
dissolved in blood, eg. peptide/protein hormones, catecholamines
hydrophobic - made on demand, released by diffusion, bound to carrier
proteins in blood, eg. steroid and thyroid hormones
peptide hormones
3 or more AA, synthesized like secreted proteins, short half life in plasma,
eg. insulin, hydrophilic so dissolved in plasma
disulfide bonds on proinsulin
regions with disulfide bonds can get off, forming insulin, and the
remaining C-peptide is a byproduct and can be used to indirectly
measure insulin release
