THE N

ERVOUS SYS

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CENTRAL NERVOUS SYSTEM (CNS)

Consists of the spinal cord and the brain

Both covered with a protective membrane called meningens

Impulses are received at the spinal cord and the brain via the PNS- initiates voluntary motor control

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PERIPHERAL NERVOUS SYSTEM (PNS)

-Lies outside the central nervous system

-Contains cranial and spinal nerves that send signals to and from the CNS

SOMATIC VS. AUTONOMIC SYSTEM

Somatic system – includes nerves that take stimuli from PNS to the CNS and motor commands from the CNS to the skeletal muscles.

Voluntary responses

Autonomic System

Regulates activity of smooth muscle and glands

Divided into the sympathetic and parasympathetic divisions

SYMPATHETIC DIVISION

Neurons arise from the middle of the spinal cord

Involved with “fight or flight” responses that are important during emergency situations.

If you need to fend of a foe or flee from danger, your muscles need a quick supply of glucose and oxygen.

To accomplish this, the sympathetic division accelerates the heartbeat and dilates the bronchi, but inhibits the digestive tract.

The neurotransmitter released during this is norepinephrine (NE)

PARASYMPATHETIC DIVISION

Involves a cranial nerves and nerves that arise from the bottom of the spinal cord

Promotes all internal responses associated with a relaxed state.

Causes the pupil of the eye to contract, promotes digestion of food and slows down the heartbeat

The neurotransmitter released during this is acetylcholine (Ach)

http://www.youtube.com/watch?v=J968Wco1u0s

THE BRAIN

MEDULLA OBLONGATA

-Lies between the spinal cord and the PONS

-Regulates heartbeat, breathing, and blood pressure

-Reflex center for vomiting, sneezing, swallowing, and coughing

CEREBELLUM

-Separated from the brainstem

-Passes on both sensory and motor information

-Maintains normal muscle tone, posture and balance

-Makes sure all skeletal muscles function together for smooth and coordinated movement (like playing the piano or swinging a baseball bat)

THALAMUS

-Integrates sensory information

-Serves as a central relay station for impulses travelling up to the cerebrum

-Involved in higher mental functions such as memory and emotion

HYPOTHALAMUS

-The integrating center for the autonomic system

-Also helps maintain homeostasis

Regulating hunger, sleep, thirst, body temperature and water balance

-Controls the pituitary gland

PITUITARY GLAND

-Located on the hypothalamus

-An endocrine glandSecretes hormones involved with growth, blood pressure, breast milk production, body temperature, ect.

-Hormonal secretion controlled by the hypothalamus

THE CEREBRUM

-Largest portion of the human brain

-Has two halves connected by the corpus callosum

-Highest center to receive sensory input and carry out integration before commanding voluntary motor response

-Works with other parts of the brain to regulate activities

-Carries out higher thought processes required for learning, memory, language and speech