Gas Exchange
Explain how lungs and respiratory system organs move during inhalation using the terms of volume and pressure
diaphragm contracts --> lung volume increases/lung pressure decreases --> pressure gradient created (Patm>Plung) --> air comes in
True or false: neurons can deliver both electrical and chemical signals. Explain your reasoning for your choice.
Name the 5 types of sensory receptors we talked about. Briefly explain what each receptor type detects.
1) Chemoreceptors- detect solutes, tastes, smells
2) Mechanoreceptors- detect sound, touch and motion
3) Photoreceptors- detect light
4) Thermoreceptors- detect heat and cold
5) Pain receptors (nociceptors) = noxious chemicals and temperatures
Describe the forms in which O2 and CO2 are transported in blood
CO2= dissolved in plasma as bicarbonate; bound to de-oxy Hb, or just CO2
Name the 5 steps occuring on the AP graph. What ions are moving and in what direction (ie. in/out of the cell) in each step and through which transporter(s)? Be as specific as possible when naming the transporters.
1. resting state: Na+ out and K+ in via Na+/K+ pump
K+ out via K+ leak channels
2. depolarization: Na+ in via ligand-gated Na+ channels
3. rising phase: Na+ in via VG-Na+ channels
4. falling phase: K+ out via VG-K+ channels
5. hyperpolarization: K+ out via VG-K+ channels
Label the following muscle types as striated or not striated: skeletal, cardiac and smooth muscle
ans= skeletal and cardiac are striated; smooth muscle is NOT striated
What are the x and y axes of a Hb dissociation curve with units?
x axis= PO2 (mm Hg)
y axis= % Hb saturation
Explain what allows for AP to travel in only one direction.
- refractory period caused by Na+ channel inactivation and also the hyper polarization step
What four functional areas of the cerebral cortex are involved in the following scenario? Please put them in order. "Martha sees smoke coming out of the cooking pot and then right after she hears the fire alarm go off. She quickly runs to the gas to turn it off but accidentally touches the hot cooking pot."
visual cortex → auditory cortex → motor cortex → somatosensory cortex
Alex enters a room with 21% CO2, which part of ventilation is most affected: inhalation or exhalation? Also explain how the respiratory volume is affected.
exhalation; less air will be moved out of the lungs because small pressure gradient
You are testing a drug that binds to receptors on the postsynaptic cell membrane. You then measure the receptor potential of the postsynaptic cell and find it to be hyperpolarized. Would you say this drug mimics glutamate or GABA? Explain the potential mechanism for how either an IPSP or EPSP was caused in the postsynaptic cell.
True/False: Because photoreceptor cells are non-neuronal, they can only generate AP, but not receptor potentials.
False
Name 2 factors that can affect hemoglobin-oxygen affinity and answer the following prompt: After exercising you decide to take a cold water plunge to help reduce muscle soreness. Will your hemoglon dissociation curve shift left, right, or no shift in response to this cold water? How does the amount of oxygen available to your body tissues compare to before immersing yourself in cold water (ie. more oxygen/less oxygen/the same)?
- factors affecting affinity= pH, temperature, global proteins
- shift L= so less oxygen available to body tissues
You are a mad scientist and you have developed the drug CAT. CAT decreases the extracellular concentration of Na+, K+ and Ca2+. If an AP has already been generated in the presynaptic neuron, how will adding CAT affect the postsynaptic potential? Explain.
decreased Ca2+ influx into synaptic terminal--> decreased exocytosis of NT --> less NT binding to receptors on postsynaptic membrane --> decreased postsynaptic potential
Are photoreceptor cells depolarized or hyperpolarized in resting conditions? What is the FIRST step that occurs once a photon (light particle) hits the retina?
depolarized; retinal absorbs the light and goes from cis to trans conformation