Lecture 25 Flashcards
What is the function of aldosterone?
steroid hormone = increases sodium reabsorption
Which structures of the nephron does it act on?
distal tubule and collecting duct
What secretes aldosterone?
adrenal cortex
What are the 2 triggers for aldosterone secretion?
increase extracellular potassium | decrease BP
What initiates the angiotensin II pathway?
decrease in BP
What is the affect of the atrial natriuretic peptide?
increase sodium excretion = opposite of aldosterone
What are P-cells?
parietal epithelial cells responsible for sodium reabsorption
What is the rectifying channel?
preferential movement/direction of ion flow
How can penicillin excretion be delayed?
penicillin and probenecid compete for the same transport system
What are the 5 special senses?
vision | hearing | taste | smell | equilibrium
What are the 5 somatic senses?
touch | temperature | pain | itch | proprioception
What is proprioception?
spatial orientation of body parts
What are the 3 kinds of sensory neurons the body uses to get info from the environment?
simple receptors | pacinian corpuscle | hair cells
What are simple receptors?
free-nerve endings | sensitive to touch | found on cornea
What is the pacinian corpuscle?
enclosed nerve endings with layers of connective tissue
What are hair cells?
mechanoreceptors | found in ear
What are chemoreceptors?
detects levels of molecules such as O2 and glucose
What are mechanoreceptors?
detects movement of air or pressure such as vibrations or cell stretch (osmoreceptors)
What are photoreceptors?
detects photons of light
What are thermoreceptors?
detects varying degrees of heat
What is transduction?
conversion of stimulus energy into info that can be processed by the CNS | via open/close of ion channels and second messenger systems
What is two-point discrimination?
when 2 points can be perceived as 2 different stimuli because the secondary neurons are not converging
What happens when the secondary sensory neurons converge into 1?
creates a larger receptive field = allows stimuli to be summed up as 1
Do all parts of our bodies have 2-point discrimination?
no = different sensory systems throughout the body
What are sensory modalities?
different senses such as temp and touch
Where is the relay system that all sensory modalities pass through?
thalamus
Which sensory system does not pass through the thalamus?
sense of smell = olfactory
What does modality mean?
nature of the stimulus (if it is taste or smell)
What are the 4 factors that the CNS uses to differentiate between the different senses?
modality | location | intensity | duration
What happens if the stimulus continues?
nerve endings will at some point = no longer trigger CNS to relay the info = desensitization to the stimulus
What is lateral inhibition?
multiple signals coming in = whichever dominates will inhibit the neighboring secondary neurons
What is decussation?
when signals switch from one side of the brain to the other
What is homunculus (little man)?
mapping out the somatic sensory cortex and how each part of the cortex reflects that stimulus that comes from the body
