Bio Ch. 11 Notes - BIOL 2221 Fall 2016 Chapter 11 Lecture...

BIOL 2221 Fall 2016
Chapter 11 Lecture Outline—Fundamentals of the Nervous Tissue and Nervous Tissue
1. Nervous system functions
a. Sensory input- sensory receptors monitor changes in/outside body
b. Integration- processes & interprets sensory input & decides what should be
done
c. Motor output- activates effector organs (muscles & glands) to cause a
response
2. Nervous system organization- Fig. 11.2 & 11.3
a. Central nervous system (CNS)- integrating & control center of nervous
system; interprets sensory input & dictates motor output based reflexes,
current conditions, & past experience
i. Anatomy: dorsal body cavity
1. Brain
2. Spinal cord
b. Peripheral nervous system (PNS)- nervous system outside CNS
i. Anatomy: extend from brain & spinal cord; communication lines
1. Cranial nerves- carry impulses to & from the brain
2. Spinal nerves- carry impulses to & from the spinal cord
ii. Divisions:
1. Sensory (afferent) division- nerve fibers (axons) that convey
impulses to the central nervous system from sensory receptors
located throughout body; keeps CNS constantly informed of
events going on in/outside body
2. Motor (efferent) division- transmits impulses from the CNS to
effector organs (muscles & glands); impulses activate muscles
to contract & glands to secrete; effect a motor response
a. Somatic nervous system- somatic motor nerve fibers
conduct impulses from CNS to skeletal muscles;
voluntary nervous system  allows us to consciously
control skeletal muscles
b. Autonomic nervous system- visceral motor nerve fibers
regulate smooth muscles, cardiac muscles, & glands;
involuntary
i. Sympathetic division- prepares body for activity
or to cope with some stressor; fight, fright, &
flight subdivision
ii. Parasympathetic division- oversees digestion,
elimination, & glandular function; resting &
digestion subdivision
3. Neuroglia- aka glial cells; nonexcitable cells of neural tissue that support, protect, &
insulate neurons; Fig. 11.4
a. CNS
i. Astrocytes- most abundant & versatile; look like branching sea
anemones; support & brace neurons & anchor them to their nutrient
1

supply lines; assist in exchanges b/w blood capillaries & neurons
 help determine capillary permeability; guide formation of synapses
(junctions) b/w neurons; most important job = mopping up leaked
potassium ions & recapturing & recycling released neurotransmitters
ii. Microglia- small w/ long thorny processes  touch nearby neurons &
monitor their health & when sense injured neurons they migrate
towards them; transform into phagocytes in areas of neural damage &
inflammation
iii. Ependymal cells- range from squamous to columnar shape; lines
central cavities of brain & spinal cord  cilia helps circulate
cerebrospinal fluid that cushions brain & spinal cord
iv. Oligodendrocytes- have fewer processes than astrocytes; line up along
thicker nerve fibers in CNS & wrap processes around the fibers to
produce myelin sheath  insulating covering
b. PNS
i. Satellite cells- surround neuron cell bodies; same functions as
astrocytes
ii. Schwann cells- surround all nerve fibers in PNS & form myelin sheaths