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Circulatory System
Function: To transport materials such as oxygen, nutrients, hormones, through out your
body.
Structure: Heart, Blood Vessels, Blood
Types of Blood Vessels
Veins: carry blood towards the heart (the blood is oxygen poor except for the blood in the
Pulmonary vein)
Arteries: carry blood away from the heart (the blood is oxygen rich except for the blood in the Pulmonary
Artery).
Capillaries: very tiny blood vessels. Valuable nutrients are exchanged between the capillaries and your cells.
Blood – is a tissue made up of cells and cell parts that are carried in a liquid (plasma).
Parts of Blood
Plasma - the liquid part of blood that makes up over half the volume of blood. Plasma carries nutrients, waste
products, oxygen and minerals to the body cells.
Red blood cells –do not have nuclei but contain hemoglobin. Hemoglobin is a molecule that carries carbon
dioxide and oxygen. Function: Carry oxygen and carbon dioxide to and from the cells.
White blood cells – Help fight disease and have a nuclei, Function: fight infections by leaving the blood
through the capillary walls and going to the tissue that has be damaged.
Platelets- irregular shape cell fragments. Function: helps stop bleeding by plugging holes in small blood
vessels.
Excretory System
Excretory System – removes waste such excess water, H2O, urea, carbon dioxide,
CO2, and other wastes from our blood.
Some organs belong to more than one system.
• Skin – excretes water, as sweat, which contains some trace chemical
wastes, including urea.
• Lungs – filter out carbon dioxide, CO2, from the blood.
• Large intestine - removes solid, undigested food from the body after it
passes through the digestive system.
Urinary System: Part of the Excretory system
Kidneys – filter wastes and excess water from the blood.
Ureters – tubes that take urine from the kidney to the urinary bladder.
Bladder – muscle sack that stores urine.
Urethra– small tube that leads urine out of the body.
Endocrine System
The endocrine system is a complex collection of hormone-producing glands that control basic body functions
such as metabolism, mood, growth and sexual development.
It is made of glands that secrete hormones directly into your bloodstream
These hormones cause changes in your body
• A hormone is a “chemical messenger”
– A chemical that delivers a message
• Hormones are made in the glands of your endocrine system and secreted into your blood
• They travel through your blood until they reach special target cells
Nervous System
Structure: Nerves, spinal cord, neurons, brain
Function: It is responsible for controlling all the functions and movements in the body and allows you to respond to
changes in your environment.
Your spinal cord is made of bundles of neurons that carry electrical impulses from all parts of the body to the brain and
from the brain to all parts of your body. The joints between vertebrae are called gliding joints, where one part of
a bone slides over another bone.
All of the different structures in the Nervous System work together to maintain homeostasis
Digestive System
Digestion involves: Digestion is both physical (chewing) and chemical (enzymes). The digestive system is
where the body gets its nutrients. Large molecules are broken down into smaller molecules so that they can
pass through wall (membrane) of the digestive system. Materials can pass through this wall/ membrane,
much like air can pass through a screen on a window but insects cannot.
Mouth: Mechanical digestion - Teeth bite off and chew food into a soft pulp that is easy to
swallow. Chemical digestion – saliva
Esophagus: The esophagus is a muscular tube. It takes food from the throat and pushes it down
through the neck, and into the stomach. It moves food by waves of muscle contraction called
peristalsis.
Stomach: The stomach has thick muscles in its wall. This contract to mash the food into a water soup
called chyme. The stomach lining produces strong digestive juices. (chemical digestion)
Small Intestine: The nutrients are broken down small enough to pass through the lining of the small
intestine, and into the blood. Nutrients are carried away to the liver and other body parts to be
processed, stored and distributed. (chemical digestion)
Large Intestine: Water is absorbed. The remains are formed into brown, semi-solid feces, ready
to be removed from the body.
Rectum: Rectum’s job to receive stool from the colon, to let the person know that there is stool to
be evacuated, and to hold the stool until evacuation happens.
Anus: It lets you know whether the contents are liquid, gas, or solid. The anus is surrounded by
sphincter muscles that control of movement of stool.
Organs of the Endocrine system that help with digestion:
Liver: It stores some nutrients, and releases them into the blood according to the activities and needs
of the body (helps the body maintain homeostasis) (chemical digestion)
Pancreas: Makes digestive juices called enzymes which help to digest food. (chemical digestion)
Respiratory System
Function: To bring O2 to into the body and cells and remove CO2 from the body and cells.
Structures of the Respiratory System: Lungs, trachea, bronchioles, alveoli, diaphragm
Breathing and Air Pressure
When you inhale, the diaphragm contracts and expands the chest cavity.
When you exhale, the diaphragm relaxes and the chest cavity gets shrinks.
Muscular System
Function: For movement of the body
Types of Muscles –
Smooth Muscles- include the muscles of internal organs and blood vessels. These muscles move involuntary.
Cardiac Muscle- Found only in the heart and also involuntary.
Skeletal Muscles- Are voluntary and help you move.
Skeletal System
Structures: bone, tendons, ligaments, cartilage
Functions:
1. Gives Shape and support to the body
2. Protect your internal organs
3. Major muscles attach to bones to help you move
4. Blood cells are formed in the bone. (The tissue called marrow)
5. Store calcium and phosphorous compounds
Cartilage: covers the end of the bones. It is flexible and acts like a shock absorber.
Tendon – connect muscle to bone
Ligament – connect bone to bone
Integumentary/ Skin System
Function
1. Protection -keeps microorganisms from getting into your body and protects you from environmental
hazards like chemicals and radiation
2. Maintain body temperature by sweating or shivering
3. Maintains moisture so organs don’t dry out
4. Sense organ…allows us to feel our surroundings
5. Vitamin D Absorption
Homeostasis
Homeostasis describes an environment that supports the survival of cells. All of your body's systems work
together to maintain homeostasis inside of your body. Homeostasis is achieved by making sure the
temperature, pH (acidity), and oxygen levels (and many other factors) are set just right for your cells to
survive. Examples of Homeostasis: Stimulus – You are hot. Response – You sweat.
Stimulus: any change in an organism’s environment that causes to the organism to react. It is a fancy way of
saying “cause”.
Response: how the organism reacts to a stimulus and results in a change in behavior. It is a fancy way of
saying “effect”.
Reproductive System
The purpose of the reproductive system is to reproduce. Each gender produces a sex cell that has half of the
chromosomes of a complete cell.
Females produce eggs in their ovaries. Males produce sperm in their testicles.
Fertilization occurs when the chromosomes of a sperm and an egg combine to form a new genome.
Human gestation (development of the fertilized egg from zygote to blastocyst to embryo to fetus) takes place
in the uterus of females. Human gestation is approximately 9 months (40 weeks).