Transcript The Central Nervous System Chapter 8.3 McGraw-Hill Ryerson Biology 12 (2011) All nerves within the PNS contain a thin membrane called the neurilemma • Neurilemma.

The Central Nervous System
Chapter 8.3
McGraw-Hill Ryerson
Biology 12 (2011)
All nerves within the PNS contain a
thin membrane called the neurilemma
• Neurilemma promotes the regeneration of
damaged axons
• Grey Matter
– Nerves in the brain and spinal cord (CNS)that lack
myelin and neurilemma
• White matter
– Nerves in the brain and spinal cord (CNS) that
contain myelin and neurilemma
Central Nervous System (CNS)
• Contains the nerves of the
brain and spinal cord
– Function = coordinating
center of
incoming/outgoing
information
Central Nervous System (CNS)
• Brain is found in the skull & serves as overall
control center for the nervous system
• Spinal Cord is surrounded by vertebrae and
extends down the back of the neck, thorax and
abdomen
– Center of many reflex actions
– Provides a link between sensory and motor nerves
• Both are enclosed in 3 protective membranes
called the meninge
• Space between meninge contains cerebrospinal
fluid which protects and cushions the CNS
The Brain
• 3 big regions made up of little parts
– Forebrain
• Thalamus: sits at base of forebrain with neurons that connect
to various parts of the brain (“great relay station)
• Hypothalamus: controls blood pressure, heart rate, body
temperature, drives (hunger/thirst), and emotions.
Abnormalities is linked to violent, unusual behaviour
• Cerebrum: largest part of brain (80% of brain weight) and
divided into left and right hemispheres which contain intellect,
learning, memory, consciousness, and language
– Midbrain
– Hindbrain
The Brain
• 3 big regions made up of little parts
– Forebrain
– Midbrain
• Midbrain: found above the pons in brainstem and is involved
in sensory information (eyes, ears, nose) by relaying
information between hindbrain and forebrain
– Hindbrain
The Brain
• 3 big regions made up of little parts
– Forebrain
– Midbrain
– Hindbrain
• Cerebellum: unconscious coordination of posture, reflexes,
body movements, fine/voluntary motor skills, and receives
information from specialized sensors (proprioreceptors located
within skeletal muscles and joints)
• Medulla oblongata: coordinates reflexes and automatic bodily
fnctions that maintain homestasis such as heart rate,
constriction or dilation of blood vessels, and rate of breathing,
swallowing, and coughing
• Pons: serves as a relay centre between the neurons of the right
and left halves of cerebrum, cerebellum, and rest of the brain
The Brain
• Cerebral cortext split into 4 pairs of lobes
– Occipital lobe: receives and analyzes visual
information and is needed for recogntion of what is
being seen
– Temporal lobe: shares in the processing of visual
information but its main function is auditory reception
– Parietal lobe: receives and processes sensory
information from the skin, and helps to process
information about the body’s position and orientation
– Frontal lobe: integrates information from other parts
of the brain and controls reasoning, critical thinking,
memory, and personality
The Brain
• Glial cells: non-neural cells that maintain
homeostasis, form myelin, deals with waste
materials from neurons, and provide support
network and protection in the brain.
• Meninges: three layers of tough elastic tissue
– Located within skull and spinal column
– Directly encloses the brain and spinal cord
Blood-brain barrier
• A protective barrier formed by glial cells and
blood vessels that separates the blood from the
central nervous system
• selectively controls the entrance of substances
into the brain from the blood
– Oxygen and glucose are needed by the brain in high
and constant supply and enter the brain through
special transport mechanisms
– Caffeine, nicotine, and alcohol are lipid-soluble so
they pass directly through the lipid bilayer of the
capillaries in the brain
Cerebrospinal Fluid
• Dense, clear liquid from blood plasma found
in the ventricles of the brain, in the central
canal of the spinal cord, and with the
meninges
– Transports hormones, white blood cells, and
nutrients across the blood-brain barrier to cells of
the brain and spinal cord
– Acts as a shock absorber to cushion the brain
Homework
• Pg 369 #1, 3, 4, 8, 13,