L3 - Brain Basics Flashcards
Label the brians according to what specie(s) they belong to:
A. Bird
B. Mammal
C. Reptile
D. Bony Fish
E. Amphibian
F. Shark
G. Lamprey
Why do regions of the brain vary in size?
Neuron-rich system are energetically costly
- e.g. In humans: 20% of blood flow goes to the brain, and consumes 20% of the oxygen your body uses. (despite being only c. 2% of your body weight)
- basically use it or lose it
Lable this embryonic vertibrate brain
Top to bottom:
- Forbrain
- Midbrain
- Hindbrain
What are the cerebral “cortices” of mammals?
- The outer layers of the cerebral hemispheres
- singular - “cortex”
What does DECORTICATE** mean?
The cortices are surgically removed
What does DECEREBRATE** mean?
The entire cerebral hemispheres are surgically removed
What does VOLUNTARY mean?
In humans
- feels like we mke a decision
Also
- action can be initiated, delayed or withheld altogether based on context (often thanks to learning)
- action can be modified part-way through if not succeeding (use of feedback)
- action can be abandoned part-way through if not working (ditto)
- action can be modified over time with learning
Lable the diagram
What part of the brain is responsible for decision-making, learning, and use of feedback?
Forebrain - Telencephalon
What does UNVOLUNTARY mean?
In humans
- Feels like we do not make a decision: just happens
Also
- context does not weather or when an action is performed: happens in a ‘stimulus-response’ automatic manner
- action cannot be modified part-way through if not succeeding (no use of feedback)
- action cannot be abandoned part-way through if not working (ditto)
- action cannot be modified over time with learning
- e.g. startle reflexes
What is the function the MEDULLA?
- coordinates some unlearnt reflex actions (e.g. swallowing, vomiting, sneezing)
- also contains ‘vital centres’ that control heart -beat and breathing (also blood pressure)
What is the function of the PONS?
- mediates other unlearnt, reflex actions like startle, grasping
Some actions can be voluntary OR involuntary.
True or False?
True
- Some functions like swallowing, breathing,stepping, swimming, ect can be both
- Most of these functions are controlled by the medulla and/or spine and/ or midbrain (optic tectum) BUT can be ‘commanded’ by the forebrain too
What are some characteristics of “Anencephalic” babies lacking a cerebrum?
- They can still swallow, yawn, show grasp reflexes; have facial expressions; eyes may even follow moving objects
- all these actions are involuntary due to the fact there is no fore-brain to allow these actions to become voluntary.
“DECEREBRATE” dogs/cats can still…