Human body systems
11 interdependent systems
Digestive system
• The digestive system is made up of the
digestive tract; a series of hollow organs
joined in a long, twisting tube from the
mouth to the anus—and other organs that
help the body break down and absorb
food.
Here is how it works
• Digestion is made up of 3 parts:
mechanical digestion, chemical digestion
and absorption.
• Absorption occurs in the small intestine
when small blood vessels called capillaries
pick up the nutrients and distribute them to
the body.
Explanation of Starch Digestion
Digestive Organs
• Organs that make up the digestive tract
are the mouth, esophagus, stomach, small
intestine, large intestine—also called the
colon—rectum, and anus. The mouth,
stomach, and small intestine contain tiny
glands that produce juices to help digest
food. The digestive tract also contains a
layer of smooth muscle that helps break
down food and move it along the tract.
Diagrams of the digestive system
• Major Organs
Helpful Digestive organs
• Food never passes through the liver and
pancreas, however they are important for
digestion.
• Two “solid” digestive organs, the liver and the
pancreas, produce enzymes that reach the
intestine through small tubes called ducts. The
gallbladder stores the liver’s digestive juices until
they are needed in the intestine. Parts of the
nervous and circulatory systems also play major
roles in the digestive system.
Enzymes Play Their Part
• The following are some of the enzymes
and digestive juices which are responsible
for breaking down food/nutrients.
• Saliva has amylase-breaks down starches
• Hydrochloric acid-creates acid environment and
activates pepsin.
• Pepsin-in stomach-breaks down proteins
• Lactase-small intestine-breaks down__?
• Lipase-small intestine-breaks down____?
Organs
• Identify the parts of the digestive system.
Questions
• What is the primary function of the
digestive system?
• Predict which other body systems help the
digestive system perform this function?
• Which system is responsible for producing
enzymes that aid in breaking down
substances to be absorbed for the body’s
growth and repair?
Human Skeletal System
• The skeletal system protects vital organs
and works with the muscular system to
allow locomotion or movement.
Joints
• The area where two bones meet is called
a joint.
• There are different types of jointsimmoveable (skull), moveable (ball and
socket) , and slightly moveable
(vertebrate).
More Skeletal Jobs
• The skeletal system is also the site of red
blood production or bone marrow.
How many bones can you name?
Muscular System
• Muscles are bundles of cells and fibers.
• Muscles work in a very simple way. All they do is tighten
up--that is, contract--and relax.
• You have two sets of muscles attached to many of your
bones which allow them to move. The muscles work in
pairs, as one muscle contracts the other in the pair
relaxes. This allows extension of limbs.
• There are 630 active muscles in your body.
This is how we move our muscles.
• Muscles work in pairs. In picture b, the arm is
extended.
• What happens to the triceps when the biceps is
relaxed?
Some important muscles
• Muscles
Comparison of Muscles
• There are three types of muscles-skeletal,
cardiac, and smooth.
Three types of muscles
Type of
Muscle
Smooth
Appearance
Voluntary
Involuntary
or
involuntary
Controls
Function
movement of
internal organs.
Cardiac
Skeletal
Striated
Striated
Voluntary
Controls
contractions of
the heart.
Moves bones.
Pictures of the muscles
• Cardiac
• Smooth
• Skeletal
Interdependence of muscles and
bones
• What do our muscles and bones do for us?
Our bones give protection, storage, movement,
and blood cell formation. Our muscles work with
our skeletal system to allow us to move, make
our hearts and other organs work, and cause
our blood to circulate. The muscular and skeletal
systems work together to make our body work.
Questions
• Which of the following is directly caused by
muscle action? a. regeneration of nerves
b. healing of wounds c. release of hormones
d. extension of limbs
• Which structure in the upper arm is responsible
for raising the lower arm?
The Nervous System
• The function of the nervous system is to
recognize and coordinate the body’s
response to changes in its internal and
external environments.
• The primary organs and tissue are the
brain, spinal cord, and peripheral nerves.
Nervous System
• The two parts of the nervous system are
the peripheral and central (brain and
spinal cord) systems.
Diagram of nerve cell
• Neuron-nerve cell through which an
impulse travels.
Types of Neurons
• Interneuron-connects two neurons.
• Sensory- unipolar neurons responsible for
converting external stimuli from an organism's
environment into internal electrical impulses.
• Motor-control muscles.
How does a neuron work?
• Neurons carry nerve impulses in the form of
electrical energy which is then converted into
chemical energy.
• Neurotransmitters are produced by the axon
terminals in the neuron to transport the message
across the synapse.
• Synapse is the space between 2 neurons.
Nerve impulses
• Impulses move from the axon terminals of
one neuron to the dendrites of the next
neuron.
• The space between the neurons; the
synapse, is crossed by the
neurotransmitters. Neurotransmitters are
chemicals produced by the axon terminals.
• Neurotransmitters convert the electrical
impulse into a chemical message.
Diagram of an Impulse
The Brain
• The brain is the control center of the body.
• The largest part is the cerebrum. The
second largest part is the cerebellum.
Question
• In the diagram, one cell creates and releases
chemicals that travel to a second cell and quickly
induce that cell into action. This diagram
represents part of the
a. endocrine system
b. skeletal system c. muscular system
d. nervous system
The Immune System
• The immune system is also called the
lymphatic system.
• The function of the immune system is to
help protect the body from disease.
• The lymphatic system collects fluid lost
from blood vessels and returns it to the
circulatory system.
The Immune System
• The lymphatic system with the lymph
nodes, thymus, spleen, bone marrow, and
tonsils keeps us healthy.
How does it work?
• The immune system recognizes pathogens and
acts to remove, immobilize, or neutralize them.
• The immune system is antigen-specific
(responds to specific molecules on a pathogen)
and has memory (its defense to a pathogen is
encoded for future activation).
• First line of defense-the skin.
• Second line of defense-inflammatory responsereaction to tissue damage caused by injury or
infection causes the production of millions of
white blood cells.
Inflammatory response
Let’s make it Clearer
• Antigen-special surface proteins
Types of B and T cells
• B cells produce antibodies.
• T cells are produced in the thymus. Types of T
cells-Inflammatory T cells which recruit
macrophages and neutropils to site of infection
or tissue damage.
• Cytotoxic T cells and natural killer cells-kill virus
infected cells or tumors.
• Helper T cells-enhance production of antibodies
by B cells.
Question
•
a.
b.
c.
d.
Which system of the body would be
directly affected if a large number of T
cells were attacked by a virus?
Cardiovascular system
Immune system
Endocrine system
Respiratory system
Circulatory System
• The function of the circulatory system is to
bring oxygen, nutrients, and hormones to
cells. Helps fight infection, removes cell
waste; helps to regulate body temperature.
Major Organs and Tissue
• The heart-muscular organ which pumps the
blood throughout the body.
• Blood vessels-arteries, veins, capillaries.
• The blood-red blood cells, white blood cells,
platelets, and plasma.
Vascular Tissue
• Vein-thin type of blood vessel. When blood is taken, it is
taken from the vein because it is thinner and is able to
repair itself and stop the bleeding faster.
• Artery-thick blood vessel which can withstand
more pressure. (Contains smooth muscle.)
Vessels and Blood
• Capillaries are the smallest blood vessels. The
picture shows red blood cells moving through
the capillary.
• Blood is composed of red blood cells, white
blood cells and plasma. Hemoglobin is a protein
which transports oxygen in the blood.
Blood Circulation
Question
• Hemoglobin caries oxygen to body cells.
Which body system contains hemoglobin?
a. circulatory system
b. respiratory system
c. endocrine system
d. nervous system