Download Lies outside the central nervous system

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 gland
Secretes 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