Cardiovascular System And Sensory Organs Flashcards
what is an advantage of the mammalian heart having pulmonary and sysemic segregation?
differences in blood pressure
systemic bp nearly 10x more
what is the anatomy of the fish cardiac structure?
- sinus venosus (pre-pump)
- atrium
- ventricle
- bulbus arteriosus (extra ‘push’)
- simple linear circulation
what is the anatomy of the amphibian cardiac structure?
- single outflow
- 2 atria, 1 ventricle = slight mixed but segregated blood flow
- spiral valve = blood input + output frim different directions
- superior vena cava -> sinus venosus -> right atrium
what is the anatomy of the three-chambered (non-crocodillian) reptillian cardiac structure?
- 2 atria, 1 ventricle BUT partial septum
- 2 aorta, 1 pulmonary trunk
- into heart from right side (no left outflow), exit pulmonary artery
- septum positioning differs with reptile class
what do all vertebrate embryo’s hearts display during development?
branchial arch arterial arches (maintained in fish)
which vessel does amphibian blood flow through from the systemic arches?
dorsal aorta
what is seen in amphibia but not reptiles in terms of cardiac vessels?
cutaneous arteries
what big difference is there in anatomical layout of mammalian cardiovascular system compared to lower vertebrates?
breaking of left/right symmetry: mammals have only one aorta on the left
what are branchial arch arteries?
arteries supplying blood around the body of fish
only found embryonically of non-fish vertebrates + fish
hippocampal pathway
- enterial cortex signal from parahippocampal gyrus to dendrate gyrus (along perforant axons)
- mossy fiber axon -> schaffer collateral axon
hippocampal lesion experiment
- lesion on entorhial cortex, fornix, fimbria and hippocampus
- radial arm maze
- repetition of sequence of choice even when wrong
- = important for spatial learning, not queued learning
correlations between food-cathing bird and hippocampal size?
- larger hippocampus
- more neurogenesis (especially in autumn)
where in the hippocampus are place cells located?
CA1 + CA3
what do CA1 neurons do?
- predict direction
- specific firing in stem when preparing left/right turn
where are head direction cells found?
post-subiculum
ensemble code
groups of neurons firing together when in same location in space
where are grid cells located?
entorhinal cortex
what is the foramen of panizza?
- hole which connects the left + right aorta
- operates when crocodile holds its breath = shunting vessel
Path integration
Using a range of internal movement cues to determine position relative to starting point
Edward Tolman radial maze experiment method
-Put a rat in a round thing with a tunnel leading via a circuitous route to some food until rat learns there’s food there
-Block that tunnel, add a bunch of straight tunnels projecting out in a semicircle and put food in the same place as before
Edward Tolman radial maze experiment results
-Rat realises original tunnel is blocked and finds alternative route to the same spot where the food was.
-Rats are capable of dead reckoning by path integration
Reference memory example
Remembering where something was last time
Working memory example
Remembering where you’ve already looked for something
Morris water maze
-Put a rat in water with some visual clues to act as landmarks and a platform submerged somewhere in the water
-Rat will get quicker over time at finding the platform using the landmarks
-Other mazes demonstrating the same principle include elevated platform maze and elevated honeycomb
Hippocampal circuit
Entorhinal cortex–> dentate gyrus–> CA3–> CA1–> subiculum
Components of tri-synaptic circuit
-Perforant
-Mossy fiber
-Schaffer collaterals
What effect did injuring the entorhinal complex, fornix, fimbria and hippocampus of rats have?
Rats repeated the same choices even when incorrect, demonstrating deficit in spatial learning but not cued learning
Three key conclusions of maze experiments
-Hippocampal lesion/injury affects spatial learning more than cued learning
-Timing of lesion (before or after learning) is significant
-In animals with hippocampal lesions, performance was worse in working memory tasks than reference memory tasks
Three examples of hippocampal size variation
-Hippocampus of black capped chickadee gets bigger and has more neurogenesis occurring in Autumn
-Homing pigeons have larger hippocampus than non-homing relatives
-Taxi drivers have larger posterior hippocampus than other humans
Place cells key characteristics
-Located in CA1 and CA3 of hippocampus
-Firing rate of each cell increases when in a particular place
-Different cells fire in different places, forming a spatial map
Head direction cells key characteristics
-Located in post-subiculum
-Each cell is active when facing a particular direction
-Different cells fire when head facing different directions
Grid cells key characteristics
-Located in entorhinal cortex
-Fire at regular intervals according to distance traveled in any direction
-Provides most entorhinal spatial input to CA1 and CA3
Key characteristics of social place cells in bats
-Hippocampal CA1 neurons
-Track position of another bat
