The Central nervous system Flashcards
What makes up the central nervous system?
Made up of the brain and the spinal cord
What makes up the peripheral nervous system
nerves
Structures that protect the CNS
- Bone
- The meninges
- Cerebrospinal fluid
Bone protecting the CNS
The brain is protected by the cranium, and the spinal cord runs through an opening in the vertebrae called the vertebral canal
The meningies
The meninges are found inside the bones, and covering the surface of the brain and spinal cord. They are made up of three layers of connective tissue including:
- The dura mater (attached to the bone)
- The arachnoid
- The sub-arachnoid space
- And the pia mater
Cerebrospinal fluid
- Occupies a space between the middle and inner layers of meninges
- It also circulates through cavities in the brain and through a canal in the centre of the spinal cord
- Is a watery fluid containing a few calls and some glucose, protein, urea and salts
Role of the CSF
- To act as a shock absorber
- To support the brain
- To transport nutrients
Ridges of the cerebral cortex
Gryi
Folds of the cerebral cortex
Sulci
Longitudinal fissure
A deep grove that almost separates the cerebrum into two halves, the cerebral hemispheres
Lobes of the cerebrum
- Frontal
- Temporal
- Parietal
- Occipital
Three types of tracts in white matter
- Connect various areas of the cortex within the same hemispheres
- Carry impulses between the left and right hemispheres
- Connect the cortex to other parts of the brain or to the spinal cord
Functions of the cerebral cortex
- Thinking, reasoning, learning
- Memory
- Intelligence
- Sense of responsibility
- Perception of the senses
- Initiation of voluntary muscle contraction
Functioning areas of the cerebral cortex
- Sensory areas: interpret impulses from receptors
- Motor areas: controls muscular movements
- Association areas: concerned with intellectual and emotional processes
Corpus callosum
- A wide band of nerve fibres that lie underneath the cerebrum at the base of the longitudinal fissure
- Nerve fibres in the corpus callosum connect the left and right hemispheres of the brain
Cerebellum functions
- Exercises control over posture and balance
- Co-ordination of voluntary muscle movement
- Receives sensory information from the inner ear
- Receives sensory information from stretch receptors in the skeletal muscles
- All processes are sub-conscious
The hypothalamus regulates
- The autonomic nervous system (HR, BP, digestive juices, movement of alimentary canal, pupil diameter)
- Body temperature
- Food and water intake
- Patterns of waking and sleeping
- Contractions of urinary bladder
- Emotional responses
- Secretion of hormones
Medulla oblongata
- It is a continuation of the spinal cord
- It is about 3cm long and extends from just above the point where the spinal cord enters the skull
Contains: - The cardiac centre: regulates the rate and force of the heart beat
- Respiratory centres: control rate and depth of breathing
- Vasomotor centre: regulates diameter of blood vessels
Spinal cord
- a cylindrical structure that extends form the foramen magnum to the L2
- approximately 44cm long
- enclosed in the vertebral canal
- three meningeal layers
- the dura mater is not joined to the bone, allowing the cord to bend when the spine is bent
- white matter surrounds the grey
Central canal contains CSF
Functions of the spinal cord
- carry sensory impulses up to the brain and motor impulses down from the brain
- integrate certain reflexes
