Chapter 4 - Nervous system Flashcards
what makes up the nervous system
The brain, spinal-cord and nerves
What are the two parts of the nervous system
- Central nervous system: Brain and spinal cord
- Peripheral nervous system: Nerves that connect the CNS with receptors, muscles and glands
What are the three structures that protect the CNS
- Bone (cranium and vertebral canal)
- Meninges
- Cerebrospinal fluid
what are the meninges
membranes covering the brain and spinal cord
what are the three layers of the meninges
- Dura mater (outer layer) tough and fibrous
- Arachnoid mater (middle layer) loose mesh of fibres
- Pia mater (inner layer) delicate, contains blood vessels
Cerebrospinal fluid
protective fluid produced in the cavities of the brain. Fills brain cavities and surrounds brain, spinal-cord and the space between the middle and inner meninges
Three functions of Cerebrospinal fluid
- Protection: acts as shock absorber
- Support: brain is suspended in cranium and floats in fluid surrounding it
- Transport: Forms from blood and circulates around the CNS before re-entering the blood capillaries. Takes nutrients to the cells of the brain and spinal cord and carries away their wastes
Cerebrum
Largest part of the brain. Surface is folded into convolutions to increase surface area
Grey matter
Part of the brain and spinal cord made up of nerve cells and unmyelinated fibres
Cerebral cortex
Outer layer of the cerebrum made up of grey matter
White matter
Part of the brain and spinal cord made up of myelinated fighters
Basal ganglia
Masses of grey matter inside each cerebral Hemisphere
Frontal lobe
Thinking, problem-solving, emotions, personality, language, control of movement
Parietal lobe
Processing sensations (temperature, touch, taste, pain and movement)
Temporal lobe
Processing memories, receives auditory information
Occipital lobe
Vision
Insula
fifth lobe deep inside brain. Recognition of different senses and emotions, addiction and psychiatric disorders
what are the three functional areas of the cortex
- Sensory areas: interpret impulses from receptors
- Motor areas: control muscular movements
- Association areas: intellectual and emotional processes (reasoning, judgement, personality)
Cerebral cortex function
Higher order functions such as thinking, reasoning, memory, learning, awareness of surroundings
Corpus callosum
Large bundle of nerve fibres that connects and acts as communication between the two hemispheres.
Cerebellum function
Coordination of fine contractions of muscles, posture, balance
Hypothalamus function
Homeostasis, heart rate, blood pressure, digestive system, appetite, thirst metabolism, body temp,
Medulla oblongata function
Under influence of hypothalamus, regulates heart, breathing and diameter of blood vessels
Spinal cord function
Provides a pathway for communication between muscles and glands in the brain
What is the PNS composed of
- Nerve fibres (carry info to and from CNS)
- Ganglia (groups of nerve cell bodies outside the brain or spinal cord)
Cranial nerves
twelve pairs of nerves that arise from the brain (eg, Optic and auditory nerve)
sensory fibres
Fibre that carries impulses into the CNS
Motor fibres
Fibre that carries impulses away from the CNS
Spinal nerves
thirty one pairs of nerves that arise from the spinal cord. joined to spinal cord by dorsal and ventral roots
Ventral root
Contains the axon of the motor neurons that have the cell bodies in the grey matter of the spinal-cord
dorsal root
Contains axons of sensory neurons that have the cell bodies in a small swelling on the dorsal route called the dorsal root ganglion
Afferent division of PNS
Carry impulses INTO the CNS by sensory neurons from receptors in the skin and around the muscles and joints. further divided into: Somatic sensory neurons (brings impulses from the skin and muscles) and Visceral sensory neurons (brings impulses from the internal organs)
Efferent division of the PNS
Carry impulses AWAY from the CNS. divided into the somatic division (takes impulses from CNS to the skeletal muscles) and the autonomic division (carries impulses from CNS to heart muscle, involuntary muscles and glands)
What are the two divisions of the autonomic nervous system
Sympathetic division (opposes function of parasympathetic) and parasympathetic division (opposes function of sympathetic)
Fight or flight response
A response preparing the body for increased activity. Brought about by stimulation of the sympathetic division of the autonomic nervous system
compare the autonomic and somatic divisions of the PNS
