FUPAP LECTURE 8

axon hillock

the cone-shaped area on the cell body from which the axon originates

axon proper

middle of axon

axon terminal

The endpoint of a neuron where neurotransmitters are stored

site at which the axon comes in contact with other neurons at the synapse

what type of cells make up the nervous system?

neurons and glial cells

where does neuron to neuron communication occur ?

synapse b/w the axon terminal of a pre-synaptic neuron and the dendrites of a post synaptic neuron

What does the myelin sheath do?

It covers the axon of some neurons and helps speed the propagation of a nerve impulse

What does the node of ranvier do?

contains voltage-gated sodium channels

It works by speeding up the transmission of electrical signals by allowing the impulse to jump from node to node

What is a dendrite?

the bushy, branching extensions of a neuron that receive messages and conduct impulses toward the cell body

What is a dendritic spine?

small sacs of membrane that protrude from dendrites of some cells to receive synaptic input

what is dendritic spine sensitive to ?

type and amount of synaptic activity

what is the function of the brain ?

controls basic fundamental life processes as breathing, organ function etc

complex functions : thoughts, dreams, emotions

what is the function of the spinal cord ?

- carries motor and sensory information

- contain motor neurons that allow for movement and motor tracks that carry info for movement down from the brain

- receives sensory info from the periphery of our bodies and contains pathways by which that sensory info is transmitted to the brain

What is an axon?

neuronal projections that transmit nerve impules within the nervous system

What are the three anatomical planes of the brain?

Coronal

Sagittal

Transverse

Coronal plane

Divides brain into anterior and posterior portion

Sagittal plane

Divides brain into left and right

Transverse plane

Bisects brain horizontally, allowing for superior view

what are three major brain regions?

Forebrain

Brainstem

Cerebellum

What does the forebrain consist of?

Consists of the cerebrum and diencephalon

What does the brainstem consist of?

consists of midbrain, pons, and medulla oblongata

what does the cerebrum consist of ?

consists of the cerebral cortex + subcortical structures

How many lobes is the cerebral cortex divided into?

4

what are the lobes of the cerebral cortex ?

frontal lobe

temporal lobe

parietal lobe

occipital lobe

function of frontal lobe

major motor control areas and behaviour

- controls voluntary movement

- controls behaviour

- attention, planning and decision making

- motivation and emotional regulation

function of temporal lobe

auditory processing and interpretation and memory

Receptive aphasia is a condition where there is a major impairment of language comprehension

function of parietal lobe

sensory processing and interpretation ( touch)

equilibrium and balance of the body

People with dyslexia have reduced levels of activation of the left parietal lobe

function of occipital lobe

visual processing and interpretation

Patients with schizophrenia were found with abnormal activity levels in the occipital lobes

Where is the hippocampus located?

temporal lobe

what is the function of the hippocampus

- learning

- memory formation and retrieval

- regulation of hypothalamus pituitary-adrenal formation (HPA) axis

What is anterograde amnesia?

inability to form new memories

What is retrograde amnesia?

Inability to remember events in the past

What is the basal ganglia?

a set of subcortical structures that regulate movement

what neural structures make up the basal ganglia ?

caudates

putamen

globus pallidus

what is the corpus striatum?

caudates + putamen

What is the lentiform nucleus?

putamen and globus pallidus

What is Huntington's disease?

degeneration of GABA neurons in the caudate and putamen can lead to motor problems like involuntary jerking of limbs

what is parkinson's disease

degeneration of dopamine neurons in the substantia nigra that prjoects to the the caudate and putamen leads to motor problems like resting tremor

Where is the diencephalon located?

between cerebrum and midbrain

What does the diencephalon consist of?

thalamus and hypothalamus

What is the function of the thalamus ?

- relay between sensory ( except olfaction) and motor systems and the cerebral cortex

- regulate arousal, pain, mood and motivation and cognitive functions

What is synaesthesia?

- caused due to thalamic damage

- blending of information streams

- caused due to changes in the organisation of thalamic connectivity

where is the thalamus located ?

top of brainstem

Where is the hypothalamus located?

Directly above the brainstem

what is the function of the hypothalamus ?

homeostatic, reproductive and other functions

fight or flight response involves the hypothalamus-pituitary-adrenal (HPA) axis which is responsible for cortisol and adrenaline release in fight or flight response

what does hypothalamus dysfunction impact ?

HPA axis and hormone dysfunction

what is hypothyroidism

Too little thyroid hormone being produced.

what is hyperthyroidism

excessive release of thyroid hormones

Where is the brainstem located?

between spinal cord and diencephalon

what does the brainstem comprise of ?

midbrain, pons, medulla oblongata

what is the function of the midbrain?

control of eye movements and auditory and visual processing

what is the function of pons ?

relay motor info from the cerebral hemispheres to the medulla, spinal cord, and cerebellum

what is the function of the medulla oblongata?

cardiovascular and respiratory homeostasis

reflexive actions including vomiting, swallowing, coughing and sneezing

what is brainstem death ?

inability to regain consciousness or breath without support from an artificial machine

results from loss of blood circulation to all brainstem regions

What is locked-in syndrome?

awake/conscious but no production of speech, limb or facial movement

results from loss of circulation to the pons

what is the function of the cerebellum?

does not initiate movement but rather detects differences in "motor error" between intended movement and actual movement

hence aids the motor cortex produce precise and co-ordinated movement

Where is the spinal cord located?

vertebral column

how do spinal nerves communicate with the spinal cord ?

notches between the vertebrae

C1-C7

cervical vertebrae in the neck

T1-T12

thoracic vertebrae in the ribs

L1-L5

lumbar vertebrae in the lower back

S1-S5

sacral vertebrae in the pelvic area

what are the two roots of the spinal cord ?

dorsal root and ventral root

What is the dorsal root?

axons of sensory neurons that carry sensory info TO the spinal cord

What is the ventral root?

axons of motor neurons that carry info away from the spinal cord to the striated muscle

What is grey matter?

cell bodies of neurons

divided into horns

what is white matter ?

axons

divided into columns