Brain and Biology Flashcards
How many connections do brain cells have between each other?
1000-50 000. They have 160 trillion connections, 86 billion neurons.
Definition: form blood-brain barrier, repair and protect by moving toxins, and accelerate transmission.
Glial Cells
Description: receive incoming signals, branches spread out.
Dendrites
Description: single long fibre, carries outgoing messages.
Axon
Description: sustains cell’s life, processes impulses.
Soma (cell body)
Description: layer of fatty, whitish cells. Speeds up transmission, impulse jumps from node to node
Myelin sheath
What is resting potential?
When the inside of the cell is -70mV more negative than the outside. The cell is ready to fire.
What is action potential?
When stimulation makes the membrane more permeable so that more positive ions can enter the cell, causing the inside to reach threshold (-55mV), and then firing.
What happens after the cell “fires”?
Depolarization. The positive ions get pumped back out, but too many get pumped out, causing hyper polarization (-80mV). The cell goes into refractory period.
What is the process of Synaptic transmission?
- Impulse reaches terminal button.
- Neurotransmitters are released into gap.
- Neurotransmitters attach to receptor site on postsynaptic membrane. Certain NT’s fit in certain receptor (key in lock).
Description: Fight or flight. Automatically mobilizes body’s resources. Prepares body for action during emergencies. Examples: dilates pupils, digestion slows down, etc.
Sympathetic Nervous System
Description: Rest and digest. Once emergencies are over, brings bodily functions back to normal. Conserves energy while relaxing.
Parasympathetic Nervous System
Part of the brain that controls breathing, heart rate
Medulla
Part of the brain that connects cerebellum to cortex
Pons (bridge)
Part of the brain that regulate arousal; screens incoming messages (attention)
Reticular formation
Describe the cerebellum
Has 2 hemispheres.
Balance, posture.
Coordinates motor activity (smooth movements, ex riding a bike)
Predicts sensation (tickling ones self, ex ignoring a feeling on the skin)
Part of the brain that takes up the largest area
Forebrain
Forebrain structures are:
Thalamus, hypothalamus, limbic system
Describe what the Thalamus is used for.
It sits on the brainstem so it can relay incoming messages from sense receptors to the cerebral cortex.
Describe what the Hypothalamus does.
"Fighting, fleeing, feeding, fucking" Monitors eating and drinking, sexual behaviour. Biological rhythms and cycles Emotional behaviour Maintains homeostasis
Describe what the Limbic system does.
- Memory and emotion*
- olfactory (smell)
- Includes the hippocampus
- and Amygdala
What is the job of the hippocampus?
Formation/creation of new memories, spatial and emotional memories. Remember Henry Molaison.
What is the job of the amygdala?
Perception of fear, anger, sadness, controlling aggression. Holds memories involving these emotions and regulates aggression. Ex: if ever bitten by dog, the amygdala may help in processing that event and may increase your fear surrounding dogs.
The cerebrum?
Highest mental functions.
Two symmetrical hemispheres:
1. Contralateral (crosses over medulla)
2. Right/Left lateral functions
Has folds (tissues) so it can store more information in the given surface area.
What are the 4 regions (lobes) in the hemisphere?
- occipital (sight)
- temporal (hearing)
- frontal (thought and reasoning, personality)
- parietal (touch)
In split brain patients, if they are shown a picture in their right eye, will they remember what they saw?
Left eye?
They will know what they saw if shown through right eye. Will not know if shown through left eye.
