Download Central Nervous System

Nervous System: coordinates and controls body
activity. It detects and processes internal and external
information and sends out an appropriate response.
Major structures of nervous system: brain, spinal cord,
peripheral nerves, and sensory organs.
Two major parts of the nervous system are:
 Central Nervous System (CNS) = portion of nervous
system that consists of brain and spinal cord; receives
all signals from the PNS and coordinates all activities
of the body.
Peripheral Nervous System (PNS) = portion of
nervous system that consists of the cranial and spinal
nerves, autonomic nervous system; detects stimuli and
informs CNS; carries signals to cause a response at
the level of muscles and glands.
Divides into two systems:
Sensory somatic system – operates all
motor activity of the body
Autonomic system – has two divisions
(sympathetic and parasympathetic); controls
the internal environment of the animal
Sympathetic: provides
emergency and stress
response; “fight or flight”
Parasympathetic: returns body
to normal after stressful
response; maintains normal
body functions
Dilates pupils
Contracts pupils to normal size
Dilates bronchi
Constricts bronchi
Increases heart rate
Decreases heart rate to normal
Slows gut activity
Increases gut activity
Decreases saliva
Increases saliva
Homeostasis: process of maintaining a stable internal body environment
Most basic unit of the nervous system
that conducts electrochemical signals
along its length.
1. Sensory Neurons: deliver signals from a
specialized receptor to the CNS
2. Interneurons: deliver a signal from one
neuron to another; aka associative neurons or
connecting neurons
3. Motor neurons: deliver a signal from CNS to
the muscle or gland being stimulated for a
response
Cell body: also called a soma. Has a nucleus and is responsible for
maintaining the life of the neuron.
Dendrites: root-like structures that receive impulses and conduct
them toward the cell body.
Axon: a single strand that extends away from the cell body and
conducts impulses away from the cell body.
Dendrites and axons are also called nerve fibers. Bundles of nerve
fibers bound together by specialized tissues are called nerves.
The junction between 2 neurons or between a neuron and a
receptor is the synapse.
Junction where a nerve
impulse causes a
release of a chemical
substance called a
neurotransmitter that
allows the signal to
move from one neuron
to another.
Simplest unit of function within the nervous
system. The body reacts without requiring
conscious thought.
**No signal sent to the brain in order to cause
this motion.**
Brain: enlarged & highly developed portion of
the CNS that lies in the skull and is the main
site of nervous control.
Cranium: portion of skull that encloses and
protects the brain.
The brain divides into three regions:
brainstem, cerebrum and cerebellum.
Stalk-like portion brain that connects the cerebral hemispheres with
the spinal cord. Pituitary gland, hypothalamus, and thalamus are
found here. Controls most functions necessary to maintain life.
(Heart rate, blood pressure, respiration rate, etc.) Damage to this area
of the brain will either cause a coma or instant death.
Largest part of brain. Responsible for receiving and processing
stimuli, initiating voluntary movement, and storing information.
Thought, learning, judgment, language, and personality
Second largest part of brain. Provides coordination
in the animal’s movement & balance
Functions as a link between
the PNS and the brain.
Extends from the base of the
brain through the canal
formed by the vertebrae.
Cranial Nerves:
I. Olfactory
II. Optic
III. Oculomotor
IV. Trochlear
V. Trigeminal
VI. Abducent
VII.Facial
VIII.Vestibulocochlear or Acoustic
IX. Glossopharyngeal
X. Vagus
XI. Accessory
XII.Hypoglossal
Assignment: In your notes, draw a chart and include the following information:
Cranial Nerve Number, Name, and Function.
Composed of ductless glands that secrete
chemical messengers (hormones) into the
bloodstream.
Hormones: chemicals that are produced by a
tissue and travel into the bloodstream to inhibit or
set into motion or action in another part of the
body.
-Provides a chemical means of controlling distant
regions of the body.
-Regulated by a system of negative feedback. In this
system, a hormone is released in response to a change
within the internal environment.
-Once significant correction is accomplished, the
secretion is stopped.
-Hypothalamus: helps to control much of the body’s
entire endocrine system.
-Pituitary gland: called the master gland because of the
control it has over the body and other endocrine
glands.
Glands of the endocrine system include: pituitary
gland, thyroid gland, parathyroid glands, adrenal
glands, pancreas, thymus, pineal gland, and gonads
(ovaries/testes).
***RESEARCH ASSIGNMENT***
For each part of the endocrine system listed above, list its location in
the body, purpose and what hormones/secretions are released from
that part.