I. Human Body Systems
The eleven organ systems of the
human body work together to
1. Nervous system 7. Digestive
2. Integumentary System 8. Excretory
3. Skeletal 9. Endocrine
4. Muscular 10. Reproductive
5. Circulatory 11. Lymphatice
A. Nervous System
• Brain Coordinates the body’s
• Spinal Cord response to changes
• Peripheral Nerves in its internal and
B. Four major types of tissues in
the human body?
• 1. Muscle
• 3. Connective
• 4. Nervous
1. What is Muscle Tissue?
• Most abundant tissue in most animals
• Filled with mitochondria
• Controls both external and internal
2. What is Epithelial Tissue?
• Covers the surface of the body
• Closely packed cells
• Lines the internal organs
• Glands are made up of this tissue- saliva,
sweat, or milk.
3. Connective Tissue
• Holds organs in place
• Binds different parts of the body together.
– Tendons: bones to muscle (TBM)
– Ligaments: bones to bones (LBB)
4. Nervous Tissue
• Receives messages from body’s external
and internal environments
• Analyzes the data
• Directs the Response
– Heart: controls the rate at which the heart
C. How do you maintain
• Through a process called feedback inhibition.
• Human Body Temperature 98.6 o F (37oC).
• Hypothalamus regulates homeostasis in the
entire human body.
• Hypothalamus uses feedback inhibition to keep
warm when your cold (by shivering) or to keep
cool when your hot (by slowing down cell
• Section 1
The Nervous System
II. What is the function of
the Nervous System?
• Controls and coordinates functions throughout
the body and responds to internal and external
• The messages carried by the nervous system
are electrical signals called impulses.
• The cells the transmit these impulses are called
• Neurons have 3 categories
A. Sensory Neurons
• Carry impulses from the sense organs to
the spinal cord and brain
B. Motor Neurons
• Carry impulses from the brain and the
spinal cord to muscles and glands.
• Connect sensory and motor neurons and
carry impulses between them.
D. Anatomy of a Neuron
• Cell Body • Axon Terminals
– Nucleus – Series of small swellings .
– Cytoplasm – Located some distance
– Metabolic Activity from the cell body.
• Dendrites • Myelin Sheath-
– Carries impulses from the – Some neurons
environment or from other – Surrounded by an
neurons toward the cell insulating membrane.
body. • Nodes-
– Numerous – are places along the axon
• Axon- where there is no myelin
– Long fibers that carries sheath
impulses away from the – Allows impulse (signal) to
cell body. jump from node to node.
– Only one axon
E. Nerve Impulses
• Is a result of the inside of the cell changing
positive and negative charges.
• Four stages
– 1. Resting Potential
– 2. Moving Potential
– 3. Action Potential
– 4. Threshold
1. Resting Potential
• Voltage across its cell membrane of 70
• ATP is used to pump Sodium out and
Potassium into the cell across the
• Potassium leaks out of the cell
• Results in a negative charge inside to the
2. The Moving Impulse
• Begins when a neuron is stimulated by
another neuron or by the environment
• Travels rapidly down the axon away from
the cell body and toward the axon
• Sodium gates open allowing sodium to
enter the cell and creates a positive
3. Action Potential
• The inside of the cell is now positively charged.
• Now the Potassium gates open allowing them to
flow out of the cell
• This action restores the resting potential
(creating a negative charge)
• Self Propagating nerve impulse- at any point of
the membrane causes an impulse at the next
point along the membrane (like dominos).
• The minimum level of a stimulus that is
required to activate a neuron.
• A stimulus that is stronger than the
threshold will produce an impulse
• A stimulus that is weaker than the
threshold will produce no impulse.
• Follows the all or none principal: either the
stimulus will produce an impulse, or it
won’t produce an impulse.
• The location at which a neuron can
transfer an impulse to another cell.
– are located in the synapse
– Chemicals used by a neuron to transmit an
impulse across a synapse to another cell.
– These chemical molecules diffuse across the
gap and attach themselves to receptors on
the membrane of the neighboring cell.
Divisions of the Nervous System
III. The Central Nervous System
• Relays messages
• Processes information
• Analyzes information
• Spinal Fluid
C. Tissues in the brain and
• Three layers of
called the meninges. Meninges
• Cereberal Spinal
fluid lies between the
spaces of the Meninges
meninges. Spinal Fluid
• Brain stem
E. The Spinal Cord
• The main communications link between
the brain and the rest of the body.
• 31 pairs of spinal nerves branch out from
the spinal cord which connects the brain to
• Reflexes are processed directly in the
– Examples : blinking, sneezing
F. Peripheral Nervous System
• Transmits impulses from sense organs to the CNS and
back to the muscles’
– Spinal nerves
– Ganglia- nerve cell bodies
– Cranial nerves that control the head and neck.
• Divided into two divisions
• 1. Sensory
• 2. Motor
• Somatic Nervous System
• Autonomic Nervous System
1. SENSORY 2. MOTOR
• Transmits impulses • Transmits impulses
from sense organs to from the CNS to the
the CNS muscles or glands.
1. Somatic Nervous System 2. Autonomic Nervous
• Regulates activities that
are under conscious • Regulates activities that
control are automatic, or
– Ex: movement of the
skeletal muscles. – Ex: Heartbeat, digestive
• Wiggle your toes
• Lift your finger • 2 parts
– A. Sympathetic nervous
• Regulates activities system
without conscious control. – B. Parasympathetic
– Ex: stepping on a tack nervous system
PNS- Autonomic Nervous system
These two systems have opposite effects
on the same organ. Two different sets of
neurons and can quickly make
– Sympathetic Nervous System
• Ex: Heart Rate
– Increased: Sympathetic Nervous System
– Decreased: Parasympathetic Nervous System
Section 4 (IV)
A. Sensory Receptors
• 5 General Categories of Sensory
1. Pain Receptors
• Located throughout the body except in the
• Respond to chemicals released by
• Located in the skin, body core, and
• They detect variations in temperature.
• Located in the skin, skeletal muscles, and
• They are sensitive to touch, pressure,
stretching of muscles, sound, and motion.
• Located in the nose and taste buds, are
sensitive to chemicals in the external
• Found in the eyes, are sensitive to light
• Hearing and Balance
• Smell and Taste
• Touch and Related Senses
V. Drugs and the Nervous System
• Drugs that affect the synapse:
– 1. Stimulants
– 2. Cocaine
– 3. Opiates
– 4. Marijuana
– 5. Alcohol
Drugs and the Nervous System
• Increase heart rate
• Increase blood pressure
• Increase breathing rate
• Increase the release of neurotransmitter at some
synapses in the brain.
• When stimulants wear off- the user falls into
fatigue and depression.
• Long Term use can lead to circulatory problems,
hallucinations, and pyschological depression.
• Slow down
– Heart rate
– Breathing rate
– Lower blood pressure
• Relax Muscles
• Relieve Tension