Key Concept: The nervous system controls and coordinates - - PowerPoint PPT Presentation

• Key Concept: The

nervous system controls and coordinates functions throughout the body and responds to internal and external stimuli.

• Neurons transmit electrical

signals (nerve impulses)

• Three types of neurons:
• Sensory: sensory organs 

brain & spinal cord

• Motor: brain & spinal cord

 muscles & glands

• Interneurons: connect sensory

& motor neurons

• Draw and label a typical

neuron (p. 897)

• Cell Body: contains nucleus
• Dendrites: to cell body
• Axon: from cell body
• Axon terminals: synapse
• Myelin Sheath: insulates
• Nodes: gaps in between

• Outside: Na+, Inside: K+
• Resting potential:
• Na+/K+ Pump: Na+ out; K+ in
• Leak channels: K+ out
• Inside is negative compared to
• utside
• Action potential: moving

impulse; charges reverse; Na+ in, K+ out; must reach threshold; all-or-none principle

• Synapse: neuronal

communication via neurotransmitters

Central Nervous System (CNS)

• CNS function: relay

messages, processes information, and analyzes information

• Composed of the brain

and spinal cord

• Meninges and

cerebrospinal fluid coat and protect

Peripheral Nervous System (PNS)

• PNS function:
• Sensory: transmits info from

sense organs to CNS

• Motor: transmits info from

CNS to muscles or glands

• Composed of all nerves

and support cells outside

• f the CNS

The Brain

• Cerebrum: voluntary or conscious activities; intelligence;

learning; judgment; divided into 4 lobes

• Cerebellum: “little brain”; balance and fine movements
• Brain Stem: connects brain and spinal cord; controls

important bodily functions (i.e. blood pressure, heart rate)

• Thalamus: relay center
• Hypothalamus: recognition, appetite; body temp.,

hormones

The Spinal Cord

• Connects the brain to the

rest of the body

• Coordinates reflexes

(automatic responses)

Somatic Nervous System

• Voluntary responses

and movement

• Reflex arc: sensory

neuron, interneuron (some cases), motor neuron

Autonomic Nervous System

• Regulation of

automatic or involuntary responses (i.e. heart rate, breathing, function of internal organs, etc…)

• Sympathetic vs.

Parasympathetic (fight

• r flight & rest and

digest)