Physiology of Exercise

basic structural unit of nervous system.

• cell body- contains nucleus
• dendrite- many in one neuron- neurons receivers
• axon- only one axon in neuron

axon splits ino numerus end branches which go into tiny bulbs known as this

used for communication between a neuron and another cell.

 electrical signal that arises when stimulus is strong enough to substantially change the normal electrical charge of the neuron

electrical potential difference caused by uneven separation of charged ions across membrane. -70mV

1. Cell membrane is mre permeable to K+ than to Na+ , so K+ moves more freely

2. Sodium-potassum pumps in neuron membrane, which contain Na+-K+ adenosine triphosphatase, maintain imbalance on each side of membrane by actively transporting potassium ions in and sodium ions out. 

occurs any time the charge difference becomes more positive than the RMP -70mV, moving closer to zero. 

charge difference across membrane increases, moving from RMP to even more negative value, then membrane becomes more polarized

membranne potential changes from RMP about -70mV to value about +30mv and then rapidly returns to resting value. Lasts about only 1ms

membrane voltage which graded potential becomes an action potential

Any depolarization that does not reach threshols will not result in action potentiall but any time depolarization reaches or exceeds threshold, action potential will result. 

when segment of axons sodium gates are open and in process of generating action potential, unable to respond to another stimulus. 

axons of many nerons covered with sheath formed by myeln, a fatty substance that insulates the cell membrane. 

gaps between adjacent Schwann cells

much faster type of conduction that occur in unmelinated fibers. AP jumps from one node to next as traverses a myselinated fiber. 

site of action potenial transmission from the axon terminals of one neuron to the dendrites or soma of another. 

Two types: Chemical Synapses & Mechanical Synapses

site where a-motor neuron communicated with its mucles fibers

primary neurotransmitter for motor neurons that innervate skeletal muscle as well as for most parasympatheitc autonomic neurons

somatic nervous system

neurotransmitter for most sympatheitc autonmic neuron, can be excitatory or inhibitatory depending on receptors involved.

autonomic nervous system

an excitatory impulse that causes depolarization

an inhibitory impulse causes hyperpolarication

100 billion

Cerebrum

Diencephalon

Cerebellum

Brain stem

Frontal Lobe: General intellect and motor control

Temporal Lobe: auditory input and interpretation

Parietal Lobe: General sensory input and interpretation

Occipial lobe: visual input and interpretation

Insular Lobe: diverse function usually liked to emotion and self-preception

Responsible for control of fine and discrete muscle movement

Located in frontal lobe of Cerebrum

nerve prcoecess that extend from cerbral cortex to spinal cord

Provide the major voluntary control of skeletal muscles

memory bank for skilled motor activities

important in initiating movement od sustained and repetitive nature

ex: arm swinging during walking

Thalamus: important for sensory integration. Regulates what sensory input reaches the conscious brain and is very important for motor control.

Hypothalamus: responsible for maintaining homeostasis by regulating almost all processes that affect body's internal environment

• crucial role in coordinating movement
• Assists function of primary motor cortex and basal ganglia
• Facilitates movement patterns by smoothing out movement

• Composed of midbrain, pons, and medulla oblongata
• Connects the brain and spinal cord
• Contains the major autonomic centers that control respiratory and cardiovascular systems

• Lowest part of brain stem
• Composed of tracts of nerve fibers that allow 2-way conduction of nerve impulses
• Sensory (afferent) fibers carry neural signals from sensory receptors (skin, muscles, joints) to upper levels of CNS
• Motor (efferent) fibers from the brain and upper spinal cord transmit action potentials to end organs (muscles, glands)

• Contains 43 pairs of nerves: 12pairs of cranial nerves & 31 pairs of spinal nerves