Divisions of the Nervous System

Question 1

Fun facts

Answer 1

○ Info can travel as fast as 431 km/hr
- Fasted = alpha motor neurons in the spinal cord (431 km/hr)
- Slowest = Neutral receptors in the skin which miss the speed-boosting insulating layer called myelin sheath (1.6km.hr)
○ Neuronal cells of not divide
- Neuronal cells do not undergo cell division; they do not have growth or repair capacity
- Nerve damage Is usually irreversible and can result in loss of function
○ As the brain ages it loses neurons but can form new connections between the remaining neurons
- By the age of 20 we start to lose neurons to the process of aging
- By age 75 1/10 of neurons are gone
- Remaining neurons form new connections to make up for lost neurons
○ Brain holds about 100 billion neurons
- Each neuron is connected to 10 thousand other neurons

Question 2

Nervous system

Answer 2

○ A series of tissues and organs that are the prime communication system within the body
○ Responsible for
- Sensory input
□ Monitoring stimuli occurring inside and outside. The body
- Integration
□ Interpretation of sensory input
- Motor input
□ Response to stimuli by activating effector organs
○ Divided into
- Central nervous system
- Peripheral nervous system

Question 3

Central nervous system

Answer 3

□ At the center of the nervous system
□ Consists of the brain and spinal cord
□ Receives information from all over your body, processes that information, and then sends out messages telling your body how to respond

Question 4

Peripheral nervous system

Answer 4

□ Peripheral nerves that connect the CNS with the receptors and muscles
□ Consists of nerves that carry information to and from the central nervous system
□ Further divisions
- Sensory/afferent
◊ Carries messages to the central nervous system
- Motor/efferent
Carries messages from the central nervous system
◊ Further divisions - autonomic and somatic

Question 5

Autonomic

Answer 5

– Involuntary control of body processes
◊ Salivating
◊ Changing pupil size
◊ Heart rate
◊ Sneezing – Further divisions
◊ Sympathetic
□ Speed up
□ Increases the action of the body
□ Increased heart/breathing rate
◊ Parasympathetic
□ Slow down
□ Decreases actions of the body
□ Decreases heart/breathing rate

Question 6

Somatic

Answer 6

– Voluntary controls of body processes
◊ Movement of body
◊ Facial expressions