The Nervous System Structure and Function Flashcards
Classify the nervous system according to structure and function.
STRUCTURAL CLASSIFICATION
- Central Nervous System (CNS)
- Peripheral Nervous System (PNS) which is further broken down into Spinal nerves (Carry impulses to and from the spinal chord) and Cranial nerves (Carry impulses to and from the brain).
FUNCTIONAL CLASSFICATION
- Sensory/Afferent (Sensory receptors -> CNS). Can be somatic (from skin, skeletal muscles and joints) or visceral (from internal organs).
- Motor/Efferent (CNS -> effector organs). Can be via the somatic nervous system (conscious voluntary control) or Autonomic (involuntary) which is further separated into Sympathetic (Fight-or-fight) and Parasympathetic (rest-and-digest).
Draw a labelled diagram showing the major anatomical regions (cerebrum, cerebellum, midbrain, pons and medulla) and state the function of each.
CEREBRUM - 2 hemispheres. cortex made of grey matter and connecting fibres made of white matter
CEREBELLUM - Involved in the maintenance of balance, posture and muscle tone. Coordinates movement.
MIDBRAIN - Vision, hearing and motor control
PONS - messaging system between the cortex and cerebellum
MEDULLA - Contains the cardiac, respiratory, vomiting and vasomotor centers and therefore deals with the autonomic (involuntary) functions of breathing, heart rate and blood pressure.
DIENCEPHALON - Contains thalamus and hypothalamus
Identify the lobes of the cerebral hemisphere and state the functions of each.
FRONTAL - Motor cortex, intellect, planning, mood and social judgement.
TEMPORAL - Auditory cortex
PARIETAL - Somatosensory cortex (sensation and taste)
OCCIPITAL - Vision
PRECENTRAL GYRUS - Primary motor cortex
POSTCENTRAL GYRUS - Primary sensory cortex
Describe the arrangement of the spinal chord.
Supported and protected by the vertebral column
Continuous with brain stem
31 spinal segments and associated pairs of spinal nerves (8 Cerviacle, 12 Thoracic, 5 Lumbar, 5 Sacral, 1 Coccygeal)
Come To Leeds Shopping Centre (CTLSC).
Describe the protective membranes that surround the brain and spinal chord.
Dura mater
Arachnoid mater
(subarachnoid space)
Pia mater
Describe the production, circulation and function of CSF.
The ventricles are interconnecting chambers that produce CSF.
Lateral ventricle (x2) - cerebral hemispheres. Third ventricle - lateral walls formed by thalamus. Fourth ventricle - between brainstem and cerebellum.
Cerebral aqueduct connects the 3rd ventricle to the 4th.
Cushions and protects brain and spinal chord. Circulates nutrients and chemicals.
Draw a labelled diagram of a typical neurone and describe the function of each component.
DENDRITES - specialised for receipt of information
AXON - specialised for transmission of information
MYELIN - speeds the rate of conduction and makes sure it is unidirectional
NODES OF RANVIER - gaps in the myelin that aid saltatory conduction
GANGLION
A collection of nerve cell bodies
Distinguish between afferent and efferent neurones.
AFFERENT = Towards the CNS
EFFERENTS = (Exiting) Away from the CNS
Describe the structure and function of the myelin sheath.
Made of schwann cells
Has gaps called nodes of ranvier
Speeds up conduction of action potentials (saltatory conduction).
Describe the different classes of neurone.
BIPOLAR - Two processed coming from one cell body
PSEUDOUNIPOLAR - One axon with two branches, one to the spinal chord and one to the periphery (effector)
MULTIPOLAR - Many processes, one axon
Describe the sequence of ionic events that occurs at the synapse and describe the sequence of events that occurs at the synapse.
An action potential reaches the axon terminal.
This causes the release of Ca+
Vesicles bind to the presynaptic membrane
Neurotransmitter is released
Neurotransmitter binds to receptors on postsynaptic membrane
This causes the opening of ion channels
Na+ rushes into the cell causing depolarisation (cell goes from -70mv -> +50mv
This causes voltage gated potassium ion channels to open causing potassium to flood out
Repolarisation occurs (cell returns to normal)
Due to potassium channels being slow to close hyper polarisation occurs (refractory period)
Sodium-Potassium pump restores resting membrane potential
Describe the role of neurotransmitters in neurone-neurone communication.
Neurotransmitters carry the signal chemically across the synapse and cause the opening of the ion channels on the next neurone.
List common neurotransmitters and state in the nervous system each are released.
INHIBITORY NEUROTRANSMITTERS
Serotonin - When platelets bind to a clot
GABA - Inhibits the production of an action potential
Dopamine - Prolactin release
EXCITATORY NEUROTRANSMITTERS
Dopamine - Prolactin release
Acetylcholine (ACh) - Parasympathetic postganglionic neurones
Noradrenaline - Post ganglionic neurone of the sympathetic NS.
