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Human organ systems
• The human body is composed of 11 systems.
- Circulatory
- Immune
- Respiratory
- Digestive
- Musculoskeletal
- Nervous
- Urinary
- Endocrine
- Reproductive
- Integumentary
- Lymphatic
THE ENDOCRINE SYSTEM
• The endocrine system is made up of glands that produce and
secrete hormones (chemical substances produced in the
body that regulate the activity of cells or organs – “chemical
messengers”). These hormones regulate the body's growth,
metabolism, and sexual development and function. The
hormones are released into the bloodstream and may affect
one or several organs throughout the body (i.e. the
difference between target and non-target hormones).
• Hormones transfer information from one set of cells to
another to coordinate the functions of different parts of the
body.
• The major glands of the endocrine system are the
hypothalamus, pituitary, thyroid, parathyroids, adrenals,
pineal, and the reproductive organs (ovaries and testes). The
pancreas is also a part of this system; it has a role in
hormone production as well as in digestion.
Major
endocrine
glands
LOCATION
IMPORTANT HORMONE
PITUITARY
Growth hormone (body growth)
PINEAL
Melatonin (control sleep patterns)
THYROID
Thyroxin (control metabolism – how fast you burn fuel)
ADRENAL
Adrenaline (prepares body for stressful situations)
PANCREAS
Insulin (controls blood glucose levels)
TESTES
Testosterone (secondary sex traits, growth)
OVARIES
Estrogen, progesterone (sex traits, reproduction)
Endocrine disorders
• Diabetes – low levels of insulin
• Gigantism – high levels of growth hormone
• Dwarfism – low levels of growth hormone
• Sleep disorders / anxiety / depression – low
levels of melatonin
THE CIRCULATORY SYSTEM
• The circulatory system
in humans is the organ
system that transports
gases and nutrients
throughout the body
and carries away
wastes. The system is
made up of blood,
the heart, and blood
vessels.
Function of The Circulatory System
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Moves oxygen from the lungs to all the
body cells
Moves carbon dioxide from the body cells
to the lungs
Moves nutrients from the small intestine
to the body cells
Moves waste materials from the body cells
to the kidneys and skin to be removed
The Blood
• Blood is a type of connective
tissue that circulates through
your body, it consists of 4
components:
– Red Blood Cells (RBC)
– White Blood Cells (WBC)
– Platelets
– Plasma
Did you know…
- It takes about
20 seconds for
a RBC to
circulate the
entire body
Components of Blood
Red Blood Cells
-make up approx. 45% of blood volume
-contain hemoglobin (protein that carries O2)
-have no nucleus (when mature)
White Blood
Cells
-make up less than 1% of blood volume
-function is to fight infection
-have a nucleus
Platelets
-are actually just fragments of cells
-make up less than 1% of blood volume
-function is to clot blood
Plasma
-liquid that suspends the other 3 components
-makes up approx. 55% of blood volume
-contains dissolved materials (i.e. protein)
Blood Vessels
1) Arteries: blood vessels that carry blood away from the heart
• heart pumps blood with force so arterial blood pressure is higher than
venous blood pressure
• due to higher pressure, artery walls are thicker than those of veins
2) Veins: blood vessels that carry blood toward the heart
• contents are under low pressure so walls are thinner than those of
arteries
3) Capillaries: tiny blood vessels with very thin walls to allow substances to
diffuse between the blood and the body fluids and tissues
• are the blood vessels that link arteries and veins
• oxygen and nutrients diffuse from the blood into the surrounding tissues
• carbon dioxide and other wastes diffuse from tissues into the blood
The Heart (a pump):
●
Made of 3 types of tissue:
- Cardiac Muscle Tissue
- Nerve Tissue
- Connective Tissue
●
Consists of four chambers:
- 2 Atria (left and right atrium)
- 2 Ventricles (left and right ventricles)
Let’s explore the flow through the heart….
(from body)
(to body)
(to lungs)
(from lungs)
(from body)
Follow the path one red blood cell
could take around the body….
Circulatory System Diseases and
Disorders
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Coronary artery disease
Heart attack
Heart murmurs
Irregular heart beat
Leukemia
Hemophilia
THE RESPIRATORY SYSTEM
Review the following diagram to locate the system’s components:
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nasal cavity
mouth
pharynx
larynx (vocal cords)
trachea
bronchi
bronchioles
alveoli
lungs
diaphragm
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Air travels through the trachea to the lungs. The trachea contains many
epithelial cells that have hairlike projections called cilia. Cilia help filter out and
remove foreign materials (such as dust) that might otherwise enter the
bronchial tubes and lungs.
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The main purpose of the respiratory system is to exchange gases. Breathing
brings air into and out of the lungs, so that gas exchange can occur.
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Oxygen enters the bloodstream in the lungs by diffusion, and carbon dioxide
leaves in the same way. This gas exchange specifically takes place in the
alveoli, which are surrounded by capillary networks containing blood.
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When the blood arrives at the cells, the oxygen diffuses from the blood into the
cells. At the same time, carbon dioxide diffuses from the cell into the blood.
The Epiglottis
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The function of the epiglottis is to allow the air
inhaled while breathing to pass freely to the lungs.
It covers the larynx to prevent the solids and liquids
we consume from entering the windpipe (trachea).
While swallowing, the tongue pushes the larynx
downwards. This makes the epiglottis block the
entrance to the windpipe. Once the swallowing is
done, the epiglottis opens up for the air to pass
through the windpipe again.
If the epiglottis is absent or fails to function
correctly, a person will not be able to swallow
anything comfortably. He would cough and choke,
as anything he would swallow would enter the
windpipe. This is why it is said that a person should
not talk or laugh while eating.
Breathing
• Involves the diaphragm
(a large sheet of muscle
underneath the lungs)
and the muscles between
the ribs.
• Is an involuntary process
that we can override
while talking but only
temporarily.
• It is controlled by a part
of the human brain that
detects the concentration
of CO2 in our blood
Non-smoker vs smoker LUNGS
Respiratory System Diseases
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Tuberculosis (bacterial)
Cancers
Emphysema
Asthma
THE NERVOUS SYSTEM
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The nervous system is made up of the brain, spinal cord, and peripheral
nerves. It senses the environment and coordinates an appropriate
response.
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The core of the nervous system is the brain and the spinal cord.
This is called the central nervous system.
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The central nervous system is protected from injury by bones and by
cerebrospinal fluid.
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The peripheral nervous system consists of the nerves that carry the
signals between the central nervous system and the body. It also relays
instructions from the brain to other parts of the body to control many of the
body’s functions and responses.
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Reflexes are actions that do not require the involvement of the brain: they
occur without conscious thought. The spinal cord acts as a short cut for
reflexes.
The Nervous System
Parts of The Nervous System
Central
Nervous
System
Brain
Spinal Cord
Parts of The Nervous System
Peripheral Nervous
System
Somatic nerves
Autonomic nerves
(involuntary)
(voluntary)
Sensory
Motor
Sympathetic
Parasympathetic
Types of Nerve cells (Neurons)
• Sensory neurons
– carry impulses from sensory receptors (eye, ear, nose, skin,
tongue) to the brain
• Motor neurons
– carry impulses from the brain or spinal cord to muscles for
movement or to glands for hormone secretion
• Interneurons
– link the sensory and motor neurons in the brain and spinal cord
How Does Communication Occur?
• Nerve cells are called neurons
• Neurons use electrical signals
called impulses to communicate
with other cells
• Nerve
– Connective tissue and
bundles of neurons
Nerve Cell
(receives message)
(sends message)
Nervous System Disorders
• Multiple sclerosis – degeneration of myelin
sheath; scar tissue builds
• Concussions – jars or shakes brain inside skull
• Damaged / severed spinal cords
THE IMMUNE SYSTEM
• The immune system is our body’s protection
system.
• It is designed to defend against bacteria,
viruses, and toxins that invade your body.
• T cells  signal the invasion
• B cells  make antibodies (chemical fighters)
• Macrophages  white blood cells that EAT
Lymph nodes
• Lymph nodes are filled with white blood cells.
• Lymph nodes are located throughout the body and
swell when you’re fighting an infection because they
are having to work harder.
• The main job of the lymph nodes is to filter the
lymph (clear fluid that comes from tissues) by
eliminating antibody-coated bacteria.
Bone marrow
• Bone marrow is the spongy tissue inside of
your bones. It has blood stem cells which can
develop into any type of blood cell.
Thymus gland
• Precursor cells from the bone marrow travel
to the thymus gland and here they develop
into lymphocytes (white blood cells). Theses
white blood cells will produce anti-bodies that
fight bacteria and viruses.
Immune system disorders
• Primary immunodeficiency (born weak)
• Acquired immunodeficiency (becomes weak)
• Autoimmune disorders (destroys itself)
– ALS, multiple sclerosis, lupus, diabetes type 1
• Overactive immune system
– Allergies
– Anaphylactic shock
THE DIGESTIVE SYSTEM
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The digestive system is the organ system that takes
in food, digests it, absorbs the nutrients, and excretes the
remaining waste.
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The digestive system is made up of the
digestive tract and 3 accessory organs.
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The parts of the digestive system in
humans are shown here.
Know the parts!
THE DIGESTIVE TRACT
The tube in which the food travels through as it is digested
(mouth, esophagus, stomach, small intestine, large intestine, rectum, anus)
THE ACCESSORY ORGANS
(Liver, Gall bladder, Pancreas)
Mouth
• Breaks down food mechanically (teeth and
tongue)
• Also breaks apart food chemically with saliva
(enzymes and water)
• Saliva is produced in the epithelial tissue that
lines the mouth
Esophagus
• A tube connecting your mouth to your
stomach
• Surrounded by smooth muscle tissue which
can contract/relax without conscious thought
• Nerve tissue controls muscle contractions
• Contractions slowly move along food
Stomach
• Holds and churns food
• Lining of inside of stomach has cells that
produce digestive enzymes and acid
• Layers of smooth muscle tissue contract to
mix stomach contents
Small Intestine
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After stomach in digestive tract
Composed of smooth muscle
6m long, and narrow
Goblet cells secrete mucus
Does most digestion of food, and almost all
absorption of nutrients
Small Intestines
Large Intestine
• 1.5m long, and wider then small intestine
• Absorbs water after digestion
• Waste left over goes to rectum, then anus,
and out!
Accessory organs
Liver
• Produces bile (which breaks down fat in food)
Gallbladder
• Where bile is stored
Pancreas
• Creates an enzyme called insulin to help regulate
the concentration of sugar in our blood (either
helps store it or send it to cells)
Label the Digestive System!
THE MUSCULOSKELETAL SYSTEM
• The musculoskeletal system
includes all of the bones and
muscles in a body.
• It supports, protects, and moves
the body.
Function of the Skeletal System
• Protection
- protect vital organs in the body (eg. skull
protects brain, spine protects spinal cord,
ribs protect heart and lungs
• Blood-cell production
- bone marrow in large bones produce blood
cells and releases them into the blood
stream
• Mineral storage
- bones made up of calcium and phosphorus
giving bones strength and rigidity
• Support for your muscles
• Movement
Components of the Skeletal System
• The skeleton is composed of 3 types of
connective tissue.
– Bone
– Ligaments
– Cartilage
Bone
• The human skeleton is composed of 206
bones
• Hard and dense tissue
• Bone is composed of bone cells within a
matrix of minerals (calcium, phosphorus) and
collagen fibers
• If your diet is not high in minerals, your body
will absorb Ca and P from your bones causing
them to weaken
Structure of Bone
- Canals inside the bones contain nerves and
blood vessels
- Only a small percentage of the bone tissue is
actually living
Ligaments (connect bone to bone)
- are strong tough elastic bands of connective tissue that
can stretch
- Hold bones and movable joints together
- surround the joint to give support and limit the joint's
movement
Cartilage
• hard but slippery tissue that covers the ends of bones where
they meet to form a joint.
• made up of cells and collagen fibres and is wear-resistant
• helps reduce the friction of movement by allowing bones to
glide over one another
• Absorbs the energy from the shock of physical movement
• Found in:
– Ears, nose, esophagus, joints,
disks between vertebrae
Muscles
• Bones need muscles to move them
• There are about 600 muscles in the human body
• Made up of bundles of long cells called muscle fibres
that contain specialized proteins
Muscle
Tendons (connect muscle to bone)
• another type of tough connective tissue on each
side of a joint attach to muscles that control
movement of the joint.
Types of Muscles
• Cardiac Muscle
– involuntary
– in heart
• Smooth Muscle
– Involuntary
– in lining of organs (stomach,
esophagus, uterus, intestines)
• Skeletal Muscle
– voluntary
– Attached to bone (bicep, tricep, deltoid)
Antagonistic Muscles
• One contracts while the other relaxes
• Work together to move bones
• Ex. Bicep and tricep, hamstring and quadricep
Problems with the Musculoskeletal
System
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Arthritis
Osteoporosis
Broken bones
Torn ligaments
Torn tendons