600 mya = sponges have different tissues 550 mya = flatworm
with eyespots 500 mya = first fish 360 mya = reptiles w/lower
brains 65 mya = mammals with newer brain areas Evolution has had
half a billion years to improve on the early fish nervous
system
Slide 3
Divided into two parts: 1. Central Nervous System (CNS): Brain
and Spinal Cord 2. Peripheral Nervous System (PNS) Cranial Nerves
and Spinal Nerves
Slide 4
The nervous system is made up of nerve cells called neurons
They assist the nervous system in communication within the body,
coordination of body activities, orientation to the environment,
and assimilation of information
Slide 5
Schwann Cells and oligodendrocytes = produce myelin. Myelin
insulates neurons and increase speed of conduction Astrocytes =
maintain synaptic environment, and help repair damage
Slide 6
Slide 7
Sensory neurons (afferent): Found in skin or sensory organs and
help carry messages to the spinal cord and brain. Motor neurons
(efferent): Helps carry messages from the brain and spinal cord to
the muscles and glands. Associative neurons (interneurons): Help
carry messages from sensory neurons to the motor neurons.
Slide 8
A synapse is the space between two communicating neurons (about
1 micron) Messages are passed from the terminal branch or synaptic
knob of one cell to the dendrite of another. Neurotransmitters are
released and cross the synaptic cleft.
Slide 9
Action Potential = The transmission of an electrical impulse
Neurons are negatively charged cells when at rest. When stimulated,
Positively charged ions rush in (depolarization) If there is enough
depolarization (Threshold Level) then the action potential travels
the length of the neuron
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Slide 11
The human brain weighs about 3 lbs and consists of over a 100
billion neurons. The brain is protected by the skull and three
membranous coverings called meninges The outer cortex is known as
the cerebral cortex
Slide 12
Slide 13
The meninges consists of three layers The outermost covering is
called the dura mater The middle layer is called the arachnoid
Covering the brain itself is the pia mater
Slide 14
Slide 15
Deep within the brain 4 lined cavities filled with
cerebrospinal fluid Cerebrospinal fluid acts as a shock absorber
The fluid is formed by filtration from the choroid plexuses The
fluid transports nutrients and removes waste products from brain
cells 11-4
Slide 16
The brain itself can be divided into 4 main parts 1. Cerebrum 2
hemispheres which are made up of the 5 lobes of the brain 2.
Diencephalon controls sensory impulses and homeostasis 3.
Cerebellum aka mini-brain; controls movement and coordination 4.
Brainstem controls the more primitive functions like heart rate and
breathing
Slide 17
Slide 18
Largest part of the brain (~2 lbs) Made up of two hemispheres
that are connected by a bundle of nerve fibers called the corpus
callosum This allows the hemispheres to communicate with each
other
Slide 19
Slide 20
Frontal: personality, problem solving, impulse control,
decision making, reasoning, planning, motor function Parietal:
sensation and perception, integrating sensory information Temporal:
auditory sensation, verbal communication Occipital: visual
perception Limbic Lobe or System: emotion and regulation of
homeostasis
Slide 21
Slide 22
Thalamus: Acts as a relay station for incoming and outgoing
nerve impulses. Damage to this area may result in increased
sensitivity to pain. Hypothalamus: Considered the brain of the
brain. Stimulates the release of hormones as well as help sustain
homeostasis and play a role in the display of emotions.
Slide 23
Controls all functions that have to do with skeletal muscles.
This includes: Body orientation (balance) Muscle tone Coordination
of muscle movements (speaking, walking, writing, etc.)
Slide 24
Slide 25
Slide 26
Pons: Serves as a two-way conductive pathway for nerve
impulses. Midbrain: Contains reflex centers for vision and hearing.
Medulla oblongata: A pathway between the brain and the spinal cord.
Contains neurons for vital functions such as heart rate,
respiration, blood pressure, and swallowing and vomiting.