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 joints-immoveable (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 Cardiac Skeletal

Appearance Striated Striated

Voluntary or involuntary

Involuntary Voluntary

Function Controls movement of internal organs.

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 response-

reaction 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

• Which system of the body would be directly affected if a large number of T cells were attacked by a virus?

a. Cardiovascular system

b. Immune system

c. Endocrine system

d. 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