Week 3 - Central Nervous System (Brain)
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Two systems that control the body and maintain homeostasis
Endocrine and nervous system
The central nervous system consists of
Bran and spine
The peripheral nervous system consists of
Cranial and spinal nerve
Peripheral nervous system dived into 2 parts which are
Somatic nervous system and autonomic nervous system
What control does the somatic nervous system do?
Voluntary control of skeletal muscle
What is regulates by the autonomic nervous system?
Homeostasis is regulates by the hypothalamus by involuntary control of smooth muscle, cardiac muscles and glands
What 2 divisions can the autonomic nervous system be split into?
The sympathetic nervous system (flight or fight) Parasympathetic nervous system (rest and digest)
Function of astrocytes in the CNS
• support, brace and anchor neurons - help create blood brain barrier
Function of oligodendrocytes in the CNS
• form and maintain myelin sheath around axons
Function of the Schwann cells in the PNS
• form and maintain myelin sheath around axons - electrically insulate using their lipid protein colour (white)
Function of the ependymal cells in the CNS
• help produce CSF
Function of microgila in the CNS
• function as phagocytes within the CNS
What does grey matter consist of?
Neuronal cell bodies, dendrites, unmyelinated axons, axon terminals, neurogila
What does white matter consist of?
Myelinated axons
Arrangement of white and grey matter in the cerebral cortex and the spinal cord
In the cerebrum, white matter is predominantly in deeper areas and grey matter is more superficial. In the spinal cord, the grey matter is deeper and the white matter is more superficial
Age related changes of the Nervous System
• brain and spinal cord lose nerve cells and weight • nerve cells may begin to pass messages more slowest than in the past • waste products can collect in the brain tissue as nerve cells break down
How is a nerve impulse generated?
• electrical charge that travels along the membrane of a neuron. It can be generated when a neuron’s membrane potential is changed by chemical signals from a nearby cell.
Name 2 main ions involved in the generation of a nerve impulse
• Na+ (sodium) - K+ (potassium)
What is a continuous conduction?
• conduction occurs in unmyelinated axons. • process involves the opening of voltage gates Na+ and K+ channels located within the axon membrane along the length of the axon to propagate an impulse
What is a saltatory conduction
• it describes the way an electrical impulse skips from node to node down the full length of an axon, speeding the arrival of the impulse at the nerve terminal in comparison with the slower continuous progression of depolarisation speeding down an unmyelinated axon
Components and function of the synapse
• the electrical activity in the presynaptic Neuron triggers the release of chemical messengers, the neurotransmitters • the neurotransmitters diffuse across the synapse and bind to the specialised receptors of the postsynaptic cell
What is a synapse
• small pocket of space between 2 cells where they can pass messages to communicate
The sequence of synaptic transmission
• is the process by which one neuron communicates with another. • When the electrical impulse (action potential) reaches these synaptic vesicles, they release their contents of neurotransmitters. Neurotransmitters then carry the signal across the synaptic gap.
What is the role of calcium in the synaptic transmission
• Calcium ions trigger the release of neurotransmitter from synaptic vesicles into the synaptic cleft. The synaptic vesicles fuse with the presynaptic membrane during this process of exocytosis