The Nervous System Biology Notes

<<Functions of the System<<

Responsible for the control of the body and communication among its parts

<<System Organs (and key parts)<<

Central Nervous System (CNS)

  • Brain- controls bodily functions
  • Spinal cord- Connects the PNS and the CNS

Peripheral Nervous System (PNS)

  • Nerves (neuron)
    • Sensory: sends stimulus info to the CNS from the sensory organs (PNS → CNS)
    • Ears
    • Mouth
    • Skin
    • Nose
    • Eyes
    • Motor: sends stimulus info from CNS to the organs (CNS → PNS)
    • Ex: muscles

 

<<System Interactions<<

Nervous, Digestive & Endocrine Systems:

  • When an organism starts ingesting food, the nerves located on the tongue signal the stomach to start producing gastrin, a hormone that begins chemical digestion in the stomach.

Nervous & Muscular Systems:

  • Balance: receptors located in the muscles provide the brain with information about body position and movement

<<Common system disorders/medical issues<<

  • Stroke: When blood circulation is cut off from brain tissue and part of the brain tissue dies
    • The damage/symptoms can vary, depending on how long the stroke is and where it is located
    • Memory loss
    • Paralysis
    • Loss of sensory/organ function
    • Loss of limb function

<<Profession: Neurologists<<

Neurologists are specialists who treat diseases of the brain and spinal cord, peripheral nerves and muscles. Neurological conditions include epilepsy, stroke, multiple sclerosis (MS) and Parkinson's disease.

<<Peripheral Nervous System<<

Somatic Nervous System: controls voluntary reactions

Autonomic Nervous System: controls involuntary actions

  • Parasympathetic: When nothing is stimulating/stressing the organism out
    • Rest and digest
    • Stimulates stomach activity, slows heart rate, inhibits glucose release
  • Sympathetic: When the body is introduced with a stimulus that causes the body to prepare for action
    • Fight or flight
    • Increased heart rate
    • Stimulate glucose release
    • Digestion stops
    • Adrenaline/ Cortisol is released from adrenal glands

<<Reflex Arc<<

A true reflex arc involves only a few neurons and the information goes only from your body to your spinal cord! Your brain does not dictate the response.

 Steps in a reflex arc:

  1. Sensory Receptor – receptor that responds to a signal in the environment
  2. Sensory neuron - carries impulse to spinal cord
  3. Motor neuron - carries impulse away from spinal cord to the effector
  4. Effector - structure by which animal responds (muscle, gland, etc).