Transcript Chapter 29 Nervous and Endocrine System

The Nervous &
Endocrine System
Chapter 29
How our body’s communication
system maintains homeostasis
The Division of the Nervous System
Central Nervous System
Peripheral Nervous System
 Body to the CNS
 Brain and spinal cord
 Receives stimuli and
coordinates response
 Motor neurons, carry
impulse to muscles and
glands
 Displays response to organs and
glands
 Sensory neuron carries impulse
from sense organs to CNS
 Divided into
 Sensory
 Motor
 Somatic –conscious control
 Autonomic - involuntary
Three types of Neurons
Neuron = Nerve cell
• Sensory Neuron- carries nerve
impulse from sense organs to brain and
spinal cord, PNS to CNS
• Motor Neuron- Carries nerve impulse
from the brain and spinal cord to the
muscles and glands, CNS to PNS
• Interneurons- connect sensory
neurons with motor neurons and carry
nerve impulses between them
How an external stimuli
becomes a response
Neuron Physiology
Cell body- where most metabolic
activities take place
Dendrites- receive nerve impulse and
transmit to cell body
Axon- carries nerve impulse away from
cell body
Myelin sheath- covers axon, acts as a
insulator for electrochemical impulses
Nodes- gaps in the myelin sheath, nerve
impulse jumps from node to node
Synapse- area where one neuron
transfers impulse to an adjacent neuron
Nerve Impulse
All or None Principle
Neurotransmitters (chemicals) are released
from the axon and transmit impulse across
synapse by binding to receptor sites on
dendrite of adjacent neuron
Impulses are self-propagating, like dominos
Endocrine System
Made up of glands that release
their products into the
bloodstream.
These hormones broadcast
chemical messages
throughout the body
REFLEX
ARC
•Immediate response from our
body due to a painful stimulus
• Faster reaction time due to
the initial bypass of the brain.
•Nerve impulse takes a shorter
route through the nervous
system
Receptor → Sensory Neuron → Spinal Cord → Motor Neuron → Effector
The Endocrine system is
regulated by feedback mechanisms
that function to maintain
homeostasis
The body’s response
to a hormone is slow,
several minutes to several days
Major
Glands
Pituitary
Thyroid
Adrenal
Pancreas
Gonad
The major glands
Pituitary
Thyroid Pancreas Adrenal
Gets direction
from
hypothalamus
Metabolism Blood
glucose
Calcium
level
level
GH
ADH
FSH
TSH
T3
T4
Calcitonin
Insulin
Glucagon
Gonad
Fight or
flight
syndrome
Reproduction
and sex
characteristics
Epinephrine
Estrogen
Androgen
Progesterone
Negative Feedback
Mechanism
of Blood Glucose,
Glucagon, and Insulin