Neuroanatomy

Question 1

Identify the main subdivision of the human nervous system

Answer 1

see scheme

Question 2

Explain and apply the coordinate systems used for the brain

Answer 2

see scheme
dorsal, ventral, rostral, caudal, inferior, superior, anterior, posterior

Question 3

Locate and identify the main components of CNS

Answer 3

see scheme
pons, medulla, spinal cord, midbrain, thalamus, hypothalamus, amygdala, Pitulary gland, hippocampus, corpus callosum, cerebellum

Question 4

Identify the 4 lobes

Answer 4

see scheme
temporal, frontal, parietal, occipital lobes

Question 5

Explain the terms ‘gyrus’ and ‘sulcus’

Answer 5

Gyrus is the ridge and sulcus is the groove that appear on the wrinkled surface of the brain

Question 6

Locate and identify the primary sensory and motor areas of the cortex, and identify the sensory modalities they subserve

Answer 6

see scheme
primary motor cortex- voluntary movement, somatic sensory cortex- body sensations, primary visual cortex- sight, primary auditory cortex- hearing

Question 7

Identify the 3 main components of the neuron and describe their basic functions

Answer 7

see scheme
soma (cell body)= its nucleus and essential organelles are in there
dendrites= specialised in receiving units that collect messages from neighbouring neurons and send them on to the cell body
axon= conducts electrical impulses from the soma to distal target regions, such as other neurons or muscle cells

Question 8

Explain what action potential is, and why it is described as “all-or-nothing”

Answer 8

The AP means that the membrane regulates the flow of charged ionic particles or molecules into or out of a neuron.
At rest, neurons are charged at around -70 mV. When neurons are stimulated, the membrane becomes positive (o mV). This is depolarisation. When the membrane potential reaches a particular value (cca -50 mV) a strong depolarisation occurs, driving the membrane potential rapidly to cca +30 mV. This rapid depolarisation is AP.
“All-or-nothing” because AP are uniform in shape and intensity, rather than graded, they do not depend on the magnitude of the depolarisation apart from whether it exceeds the threshold.

Question 9

Describe synaptic transmission, and explain its role in neuronal communication

Answer 9

AP arriving at axon terminals stimulate the release of some chemicals (neurotransmitters) into the extracellular fluid separating the sending and receiving neurons. this gap is called the synapse, and the sending and receiving neurons are called presynaptic and postsynaptic neurons. neurotransmitters bind with special receptor molecules embedded in the membrane of the postsynaptic neuron. this can change the membrane potential of the postsynaptic dendrite, causing it to either depolarise or hyperpolarise.
In neuronal communication, synaptic transmission is the way in which neurons communicate when the AP reaches the axon terminals of the presynaptic neuron.

Question 10

Sensory neurons

Answer 10

carry messages from sensory organs to CNS

Question 11

Motor neurons

Answer 11

carry messages from motor cortex to voluntary muscle fibres

Question 12

Medulla

Answer 12

heart rate, blood pressure, respiration

Question 13

Pons

Answer 13

sleeping and dreaming, breathing, arousal

Question 14

reticular formation

Answer 14

consciousness, gating of incoming sensory information

Question 15

Cerebellum

Answer 15

fine motor coordination, learning, memory

Question 16

Midbrain

Answer 16

contains nuclei for motor planning and execution

Question 17

Thalamus

Answer 17

relays incoming signals from sensory neurons to corresponding areas of the brain

Question 18

Hypothalamus

Answer 18

motivation and emotion, controls secretion of hormones into the bloodstream

Question 19

Pituitary gland

Answer 19

brain’s portal to the neuroendocrine system

Question 20

Hippocampus

Answer 20

memory encoding and retrieval, spatial orientation

Question 21

Amygdala

Answer 21

motivational and emotional response to the environmental stressors

Question 22

Corpus callosum

Answer 22

white matter fibres connecting the two hemispheres

Question 23

Dendritic integration

Answer 23

Excitatory input depolarizes the dendrite, while inhibitory inputs hyperpolarize them. These diffuse along the dendrites and gather at the axon hillock. If excitatory and inhibitory inputs exceeds the threshold, action potential is released.