Functional Anatomy - Nervous System and Movement Flashcards
Differences between Fibres (FRACSFACC)
Characteristic | Slow-twitch |Fast type IIa | Fast type IIb
Fatigue level | Low | Medium | High
Recruitment | First | Second | Third
Aerobic cap. | High. | Medium. | Low
Colour | Red | White | White
Speed. | Slow. | Medium. | Fast
Fuel. | Carbs etc. | Lactic acid. | ATP-CP
Anaerobic cap| Low. | High. | High
Capillary dens | High. | Medium/L. | Low
Cross-section | Small. | Medium/L. | Large
Purposes of Nervous System
- To receive information from receptors which detect changes in the body and the external environment
- To process this information
- To use effectors to carry out the body’s responses
Structure of a Neuron
- Surrounded by a cell membrane
- Contains a nucleus that contains genetic material
- Soma: houses nucleus, centre of genetic control and protein synthesis.
- Dendrites: send messages to soma. More dendrites=more info
- Axon: sends messages to other cells
- Presynaptic terminal: Communicates with other neutrons at junctions
Sensory Neuron
- Send messages from receptors to CNS
- Eg. Touch, taste etc.
Motor Neuron
- Send messages from the CNS to muscles
- Eg. Telling bicep to contract
- Larger neurons = less control
Interneuron
- Relays information between motor and sensory neurons
- 90% of neurons are interneurons.
Effector
- Responds to a nerve impulse
- Can be a muscle or a gland
Receptor
- An organ with nerve endings that respond to stimulation
Central Nervous System (CNS)
- Consists of brain and the spinal cord
- Makes and distributes decisions etc.
Peripheral Nervous System (PNS)
- Consists of nerves and ganglia
- Divided into sensory and motor divisions.
Spinal Cord
- Cervical
- Thoracic
- Lumbar
- Sacral
- Coccygeal
Basic Properties of Neurons
- Excitable. Capable of responding to changes or stimuli.
- They can conduct electrical signals to other cells.
- They can secrete a neurotransmitter that bridges the synaptic cleft and allows the next cell to be stimulated. (Exocytosis)
All or Nothing Law
- Muscle fibres in a motor unit will only contract if a certain level of electrical impulse is reached, once this level is reached they all contract at the same time with the same force.
Muscle Contraction Force
- Known as recruitment
- Intensity of muscle contractions is controlled by the no. of motor units the brain tells to leap into action.
- Smaller motor units are recruited first, then as motor force is required larger units are recruited.
Preferential Reqruitment
- Only the right fibres for the job will be recruited.
