Anatomy and Physiology of brain - PowerPoint Presentation

Slide1

Anatomy and Physiology of brainSlide2

Brain cells

Neurons and

neuroglia

neuroglia

In CNS

In PNS

Asrocytes

Schwann cells

Oligodendrocytes

Satellite cells

Microglia

Ependymal

cellsSlide3

Neuron

Basic units of nervous tissue

Function as electrical impulse generation and transmission.

Cannot regenerate when damagedSlide4

Neuroglia/Glial cells

Makes half of the volume of CNS

Smaller than neurons and 5-50 times more numerous than neurons.

Do not propagate nerve impulses

Can regain after injury, highly growing.Slide5

Astrocytes

Star shaped cells, have many processes, largest and most numerous

Two types of astrocytes-protoplasmic and fibrous

Processes of astrocytes make contact with blood capillaries,

pia

matter and neurons.Slide6

Functions of astrocytes

strength to support neurons.

blood brain barrier.

growth and interconnection of neurons.

chemical environment for generation of nerve impulses by neurons.

learning and memorySlide7

Oligodendrocytes:

These resemble astrocytes but have fewer processes and smaller in size.

Maintain myelin sheath around the CNS axons.

A single

oligodendrocyte

may

myelinate

several neurons.Slide8

Microglia:

Small in size, contains spindle like projections

Function as phagocytes and clear cell debrisSlide9

Ependymal cells:

Cuboidal to columnar cells contain

cillia

and

microvilli

.

Lines the

ventricals

of brain and central canal of spinal cord.

Produce, monitor and assist in CSF circulation.

Form blood cerebrospinal fluid

barrior

.Slide10

Schwann cells:

Form myelin sheath around the neurons.

Single cell can line only one axon.

Participate in axon regeneration.Slide11

Satellite cells:

Surrounds the cell bodies of neurons in PNS ganglia.

Exchange of materials between neuronal cell bodies and interstitial fluid.Slide12

Meninges:Slide13

CSF circulationSlide14

C

S

F

C

I

R

C

U

L

A

T

I

O

NSlide15

CSF composition

Normal CSF secretion is 20 ml/hr or 480 ml/day

Total volume is 80-150 ml

Carries oxygen and nutrients

Contains glucose, protein, lactic acid, urea,

cations

( Na

+

, K

+

, Ca

2+

, Mg

2+

) and anions (

Cl

, HCO

3

-

)

Functions are mechanical support, chemical and nutritional.Slide16

Brain stem:

Consists of 3 parts:

Medulla

ablongata

Pons

Mid brainSlide17

Medulla ablongata

contains sensory and motor tracts extends between the brain and spinal cord.

Contains cardiovascular centre

Medullary

rythmicity area of respiratory centre

Responsible for vomiting, coughing, sneezing, swallowing and hiccupping.

Sensitive to touch, vibration and

proprioception

.

Contains 5 pairs of cranial nerves:

Vestibulocochlear

VIII

Glossopharyngeal

IX

Vagus

X

Accessory XI

Hypoglossal XII

Damage to this part cause cranial nerve alterations at the same side and paralysis in opposite side.Slide18

Pons

contains

pneumotaxic

area and apneustic

area which helps in respiration.

Have 4 pairs of cranial nerves:

Trigeminal V

Abducens

VI

Facial VII

Vestibulocochlear

VIIISlide19

Mid brain

connects cerebrum to medulla,

pons

and spinal cord.

Reflex centre for visual activities

Helps in tracking moving objects

Helps in scanning stationary objects

Eyes, head and neck movements with moving objects

Startle reflex

Sudden movement of head with noise

Have

substantia

nigra

which release dopamine and also responsible for subconscious muscle activities.Slide20

RAS- reticular activating systembrain stem consists of small clusters of neuronal cell bodies.

It maintains consciousness

Awakening from sleep

Muscle tone maintenance Slide21

cerebellumSkilled skeletal muscle movements

Posture and balance

Cognition and language processing