Lecture 2 Flashcards
4 principal parts of the brain?
Brain stem,
Cerebellum,
Diencephalon,
Cerebrum.
What does the brainstem continue from?
Spinal cord.
What does the brainstem control?
Respiratory and cardiovascular systems, swallowing, vomiting.
Where is the cerebellum located in relation to the brain stem?
Behind the brain stem.
What does the cerebellum coordinate?
What does it maintain?
movement, balance, posture.
Muscle tone.
What are the 2 principal parts of the diencephalon?
Thalamus and hypothalamus.
Where is the diencephalon located in relation to the brain stem?
Above brain stem.
Where is the diencephalon located in relation to the brain stem?
Above brain stem.
What does the diencephalon detect?
Touch/pressure/pain, hot/cold, sound, taste, smell, thirst, sleep patterns.
Where is the cerebrum located, and how well is it developed in humans?
Surrounding the diencephalon.
Very well developed in humans.
What four areas does the cerebrum feature?
Sensory, motor, association areas, and visual cortex.
What 3 things is the association area responsible for?
Intelligence, memory, emotions.
What does the outside of the cerebrum consist of? What about the inside?
Grey matter/cortex (neuronal cell bodies, dendrites). White matter (myelinated axons).
The cerebrum is divided into 2 hemispheres, but what connects them?
Corpus callosum.
What 2 words describe the cerebral cortex’s physical features?
sulci, gyri.
How many lobes is each hemisphere divided into? And what are they?
- Frontal, parietal, occipital, temporal.
Where are the Somatosensory areas located?
Anterior parietal lobe of the cerebral cortex.
Where are the Motor areas located?
Posteror frontal lobe of the cerebral cortex.
Are the association areas limited to one lobe in the cerebral cortex?
No, several.
Where do neurons receive information?
Dendrites.
How is information transmitted along axons?
Electrochemical signals/action potentials.
Is the lipid bilayer impermeable to Na+ and K+?
Yes.
2 types of ion channels?
Always open,
Gated.
3 types of gated ion channels?
Mechanically-gated, ligand-gated, voltage-gated.
What are voltage-gated ion channels involved in?
Generation and propagation of nerve impulses.
What are ligand-gated ion channels involved in?
Neurotransmission at the synapse.
What are mechanically-gated ion channels involved in?
Perception of touch.
2 types of molecules that could be a ligand?
Hormone or neurotransmitter.
What 2 forces move ions through membrane channels?
Chemical driving force (diffusion from region of high concentration to low)
Electrical driving force (retention of positive cations and expulsion of negative anions from negatively charged interior of cell).
What is the electrochemical driving force a combination of, and therefore, what does it give us?
Chemical and electrical driving forces acting on any particular ion.
Gives us nett force.
What is resting membrane potential of axon w.r.t. exterior?
-70mV.
What is the resting membrane potential (Vm) of a nerve cell?
Difference in voltage across plasma membrane when cell is at rest.
What were resting nerve potential studies initially carried out on?
Giant squid axon.
What does resting membrane potential depend on?
Concentration gradients for multiple ions across membrane, and the relative permeability of the membrane to those ions.
Why will Na+ enter the cell at rest?
15mM Na+ on the inside, 150mM Na+ on the outside, so chemical driving force acts towards the cell.
Interior of the cell is negative, so electrical driving force acts towards the cell.
What is the equilibrium potential (E)?
Membrane potential required to exactly counteract chemical forces acting to move one particular ion across the membrane.
What is the Nernst equation?
And what does E, z, Co and Ci mean?
E=(61/z)*log(Co/Ci)
E = equilibrium potential (mV) z = charge (valence) of ion Co = outside concentration of ion Ci = inside concentration of ion
What is ENa? And why does this
+60mV.
What is ENa? And why does this cause sodium to try and enter the cell?
+60mV.
Greater than resting Vm. Both chemical and electric driving force act in same direction.
What is Ek? And why does this cause potassium to try and leave the cell?
-94mV.
Less than resting Vm. Although chemical and electrical force act in opposite directions, chemical force is greater.
