Download Nervous and Endocrine Systems

Nervous and Endocrine
Systems
Maintaining a stable
internal environment.
Regulation in organisms
• Organisms use a
communication network
that involves a nervous
system and endocrine
system
• The Nervous System
consists of nerves, brain
and spinal cord. Helps you
respond to changes in the
environment. Works very
FAST!!!
Neurons
• The nervous system is
made up of many nerves
also known as neurons
• Neurons are nerve cells
that make pathways for
impulses (messages) to
travel.
• You have billions of
neurons
What can neurons do?
• Neurons can conduct and receive impulses.
• It is composed of:
• Dendrites- attached to the cell body RECEIVE
impulses
• Cell Body- contains the nucleus
• Axon- carries impulses AWAY from the cell
body
• Myelin- protection for the axon
Types of Neurons
• Sensory Neurons carry impulses to the spinal
cord and brain (attached to receptors)
• Interneurons are located in between the cell
bodies of sensory and motor neuron (it is a
bridge between the two).
• Motor Neuron carry impulses toward muscles
(effectors)
Reflexes
• The three neurons are important in a reflex arc.
• Your nervous system responds due to changes
in the environment.
• These changes are called stimuli
• Ex: Touching a hot stove.
• Hot stove is the stimulus and the response
is to move your hand
Parts to a reflex
• Receptors, also known as
sense organs. They are
sensitive to changes in the
environment. (ex: skin)
– When receptors are
stimulated impulses
(messages) are sent along
the sensory neuron to the
brain to form a response.
• The message travels along the sensory
neuron to the brain and across the
interneuron.
• A response is made. The message then
travels along a motor neuron and ends
up at the effector (muscle or gland)
2
1
1
3
4
Sequence of a Reflex
• Stimulus (Change in environment)
• Receptor (Sensory Organ) Ex: Skin
• Message travels (sensory, inter,
motorneurons)
• Effector (Muscle or Gland)
Neurotransmitters
• Chemicals of the nervous system that are
released from vesicles in the terminal branches.
• Allow messages to cross the synapse to the
next neuron.
• The synapse is the gap between two neurons.
• Without neurotransmitters messages do not
get sent or may not be received.
Synapse clip
• Toxins and Poisons such as drugs and
alcohol can affect the function of
neurotransmitters
• They can interrupt the impulses from
crossing the synapse.
• If the impulses do not cross the
message is not sent
Nervous System
Central Nervous
(CNS)
Brain and
spinal cord
Peripheral Nervous
System(PNS)
Motor Nerves
Somatic Nervous System
(voluntary actions)
Sensory Nerves
Autonomic Nervous System
(involuntary actions
Sympathetic
Nervous System
Parasympathetic
Nervous System
Central Nervous System
• Consists of brain and spinal cord
• Brain Facts:
– Protected by 3 layers of tissue called meninges.
– The space between meninges is filled with
cerebrospinal fluid.
– Meninges act as shock absorbers
– Highly convoluted  increases surface area.
(Wavy)
Parts of the Brain
• Cerebrum- divided into 2 halves and
contains the four lobes.
• The four lobes are called:
– Frontal
– Parietal
– Occipital
– Temporal
The Lobes
• Frontal Lobe– Complex thought and
motor function.
• Parietal Lobe– Contains sensory cortex
The Lobes
• Occipital Lobe– Processes visual information
• Temporal Lobe– Auditory and memory
Parts of the Brain Cont.
• Cerebellum- “little brain”
– Plays a role in coordinating movements and
posture.
– Compares intention with actual performance.
• Medulla/Pons- lower portion of brainstem.
– Controls involuntary body functions like:
• Breathing
• Heart rate
• Swallowing
Endocrine System
Endocrine System
• The Endocrine System- consists of
hormones and glands that work together
with the Nervous system to maintain
HOMEOSTASIS.
– Endocrine glands produces chemical
messengers (hormones) that are released
into the blood.
http://www.youtube.com/watch?v=VBwCBdd0ru8
Endo vs Exo
• The two types of glands that exist are
endocrine and exocrine glands.
• Endocrine- Release hormones into the
bloodstream. Ex Insulin and Estrogen
• Exocrine glands- Release substances
into ducts (tubes). Ex: Tears and Sweat
How do hormones work?
• Hormones work very much like enzymes
and antibodies
• They have specific cells that they
TARGET!!
• Target cells have receptors that
hormones bind to and cause a response.
Protein vs Steroid Hormones
• Protein Hormones (nonsteroid) work by
binding to the receptor on the cell
membrane.
• Steroid Hormones work by passing
through the membrane and binding to
the receptor inside the cell.
• (see ditto Hormone Action)
Feedback Mechanisms
• Feedback mechanisms are necessary to maintain
homeostasis in the body.
• An example of feedback is a thermostat.
• A feedback mechanism occurs when the level of
one substance influences the level of another
substance or activity of another organ.
• There are two types positive and negative
feedback.
Negative Feedback
• Examples of negative feedback that occur
include: Sweating, Changes in sugar levels,
guard cells and stomata, and thermostat.
• It works by reversing the affect due to a change in
your environment.
• Get hotSweatCool downTemp Rises
– The cycle then repeats to maintain homeostasis
•Guard cells will open
and close based on
environmental conditions
•Allows important
materials to enter
and leave the leaf
at appropriate times.
•The goal is to
maintain
HOMEOSTASIS!!
Glands of Endocrine System
• Pituitary Gland- “Master Gland”
– Front side and back side located in
the brain.
– Controls many functions of other
glands.
– 8 hormones are released from the
pituitary gland.
• Thyroid Gland– Located in neck region.
– Releases two important
hormones.
• Parathyroid Gland– Located on thyroid
gland.
– Releases 1 hormone.
• Adrenal Gland– Located above kidneys
– Release two
hormones.
– Cause “adrenaline
rushes”
• Pancreas– Located near stomach
and liver
– Releases two hormones
that control sugar
levels.
• Gonads– Male gonads Testes
– Female gonads 
Ovaries
– Regulate reproductive
system.
Diseases
• Goiter- disease of the thyroid gland.
– Occurs when there is not enough iodine in
the diet.
– Iodine is needed for the production of
thyroxin.
• Diabetes- Malfunction of the pancreas
– Too much insulin is made or not enough.
GOITER
Nervous vs. Endocrine
• Nervous system
• Fast response
Endocrine
Slow Response
• Short Term
Long Term
• Use Neurotransmitters
Use Hormones