Nervous system Flashcards
(20 cards)
main function of the nervous system?
control/communication centre of the body. it maintains homeostasis of internal processes and provides electrical stimulus that triggers skeletal muscle to contract
what is another role of the nervous system?
gathers info (sensation), interprets info (integration) and initiate response (response)
what is sensation?
gathers info about internal/external environment. sensors in the body. sensors in the body detect this.
what is integration?
interprets/analyses info gathered from sensors and then decides an appropriate action. this is usually involuntary with no conscious thought
what is response?
system responds to the info analysed. THIS WORKS CLOSELY WITH THE ENDOCRINE SYSTEM
what are the 2 primary divisions for the nervous system?
1) CNS
2) PNS
what is the CNS?
central nervous system, is the control base for the nervous system. consists of brain and spinal cord.
what are the 4 parts of the brain?
1) cerebrum
2) cerebellan
3) diencelphanam
4) brain stem
parts of the spinal cord
consists of cervical,lumbar,thoracic and sacral segments. is the communication link between the brain and PNS. IT INTEGRATES INFO AND PRODUCES RESPONSES VIA REFLEX MECHANISMS (ARC)
what is the PNS?
peripheral nervus system (all branches of nerves that lie outside of spinal cord. is divided into 2 parts :
1) somatic system-controls voluntary movement of the skeletal muscle
2) automatic system-controls involuntary functions
what are neurones?
transmit electrical impulses/messages. spinal nerves are divided into motor and sensory neurones.
what are sensory neurones?
they carry to the CNS from sensory organs. they are on posterior side of spinal cord from variety of sensory receptors.(in muscles, joints,tendons relay info to CNS)
what are motor. neurones?
they carry messages from CNS to muscles and glands. exit on anterior side of spina cord. neurones transmit impulses from CNS to sensory glands, making muscles contract and glands to secrete
what does each nerve cell have?
1) a cell body directing activities of neurones.
2) dendrites picking up impulses and transmiting them to the body
3) axon which transmits messages away from the cell(assisted by myelin sheaf)
what are the principles of muscle contraction?
info from external environment sent to CNS to be processed. The brain sends info on body position, muscles to contract, no. of units. these are stimulated to contact. muscles pull on bones=movement through sliding actions of myofilaments
All or none law
a motor unit has a single motor neurone. single motor neurone activates 5-1000 muscle fibres depending on location/function. impulse is sent down a neurone, fibres are activated. ALL OR NONE LAW OCCURS (all fibres contract at same time and force creating movement)
how many types of muscle fibres make a motor unit
1
what are the muscle sense organs? 3
1) joint receptors (found in ligaments =, joint capsule. TELL BRAIN POSITION OF JOINT)
2) muscle spinchles (in the muscle, TELL BRAIN HOW STRAIGHT MUSCLE and HOW MANY MOTOR UNITS ACTIVATED)
3) Golgi tendon organs (in the tendons, TELL BRAIN FORCE GENERATED IN MUSCLE, if force is too much they cause muscle to relax)
Golgi tendon organs play a big role in ballistic/PNF training, why?
as muscle relaxes, it can be taken further into the stretch
what are the improvements to motor fitness due to regular activity?
greater balance greater coordination greater power improved speed faster reaction time greater agility
