Draw and label a neuron (5)
- Axon hillock
- Axon (nerve fibre)
- Axon terminal
What are the types of Neurons? Draw each, Where are they found? (6)
- Unipolar Neuron (one soma without dendrites). Can also be Pseudounipolar (soma on top of middle of axon with terminals on both ends)
E.g Primary Sensory neurons in Dorsal root ganglia
- Bipolar Neuron (soma in middle, no dendrites, with one axon stretching both ways)
E.g Specialised sensory neurons in RETINA, OLFACTORY EPITHELIA
- Multipolar Neuron (multiple dendrites on soma, one axon)
E.g Brain neurons, Motor neurons, Autonomic ganglia
What length do neurones have to be to be myelinated? Why is this important? (2)
- Axons >1um are myelinated.
It allows Saltatory conduction - rapid (up to 120m/s) AP from node to node.
- If unmyelinated (<1um), conduction is slow (<1.5m/s). E.g Pain receptor.
What does afferent and efferent conduction mean? (2)
Afferent means towards CNS. E.g Primary sensory neurons.
Efferent means away from CNS e.g Motor neurons
What are the 2 types of Synpases (2)
Electrical Synapse - Neurones connected by gap junctions.
Chemical Synapse - Using Neurotransmitters. Majority of synapses are chemical.
What are Neuroglia? What are the 3 types of Neuroglia of the CNS? (4)
Neuroglia are supporting cells of nervous system.
What are the functions of Astrocytes? (3)
- Scaffolding, support and repair of neurons, as well as barrier to vessels.
- They supply nutrients and maintain ionic balance.
- They are involved in neurotransmitter uptake.
What is the function of oligodendrocyte? (2)
They are cells which have stretches of myelin sheaths that wrap around multiple axons.
What is function of Microglia? (3)
Microglia are immune cells of the Neurons, hence promote repair. They are:
Phagocytic and Cytotoxic
What is the Neuroglia of the Peripheral Nervous System? What functions does it provide? (4)
Schwann cells. Functions: - Myelinates Axons: one axon each. - Functions as Immune cell - Provides substrate for Axon growth
CNS: What matter is the Brain made up of? (3)
Brain is made up of grey and white matter.
Grey matter: Neuronal cell bodies, synapses and dendrites.
White Matter: Myelinated Axons
How is the Brain divided? (3)
- Forebrain - consists of Cerebral Hemisphere, Thalamus and Hypothalamus
- Midbrain - Some Brainstem
- Hindbrain - Rest of Brainstem and Cerebellum
What is the function of the Cerebral Hemisphere? What is the outer grey matter layer called? (2)
Processes sensory, motor information and cognition.
The outer grey matter layer is the CEREBRAL CORTEX.
What are the 4 lobes of the Cerebral hemisphere? What does each do? (4)
- Frontal Lobe - Primary motor cortex
- Parietal Lobe - Primary somatosensory cortex
- Temporal Lobe - Primary auditory and olfactory complex
- Occipital Lobe - Primary Visual Cortex
What is the function of the thalamus? (2)
It is in the centre of the Brain and relays information.
Sensory information passes via the thalamus before reaching the cortex.
What is the function of the hypothalamus? (3)
Controls Autonomic nervous system
Controls Endocrine system
What is the function of the Brain Stem? (2)
What is the function the the Cerebellum? (1)
- Connects Cortex to Spinal cord
- Controls Respiration and cardiovascular system
- Controls Muscular activity
Where does the Spinal cord start and end? (1)
What is the function of the Spinal Cord? (2)
- Starts from C1 and ends at L1.
Conveys information from Brain to Peripheral nervous system (motor)
Conveys information from PNS to brain (sensory)
What information comes in from Dorsal part of Spinal Cord and what information leaves from Ventral part of Spinal Cord?
SomatoSensory information Comes in through Dorsal part
Motor and glandular information leaves through Ventral part
What are the layers of bundles (fascicles) in an Axon in PNS? (3)
What are the 2 divisions of the Peripheral Nervous System?
- Somatic (Voluntary) Component - Supplying Skeletal muscles, skin etc.
- Autonomic (Involuntary) Component - supplying glands, viscera, smooth muscle etc.
- Cranial Nerves
Where do Peripheral nerves arise from? (2)
They arise from the Brain as Cranial Nerves
They arise from Spinal Cord as Spinal Nerves