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).