Body Systems

Levels of OrganizationRemember, the body is organized in several levels, from the simplest to the most complex. . .

Cells – the basic unit of life

Tissues – clusters of cells performing a similar function

Organs – made of tissues that perform one specific function

Organ Systems – groups of organs that perform a specific purpose in the body

The purpose of the 11 organ systems is for the body to maintain homeostasis

The 11 Body Systems-- Immune (lymphatic)system

-- muscular system

-- Respiratory system

-- Skeletal system

-- Digestive system

-- Reproductive system

-- Endocrine system

-- Nervous system

-- Circulatory system

-- Integumentary system

-- Excretory system

Acronym:I Mrs. Drencie

The Immune SystemPurpose: to remove infectious diseases and other pathogens from the human body (Body’s second line of defense.)

Major Organs and Their Functions

Skin – also called the integumentary system, the skin is the body’s first line of defense

White Blood Cells – recognize disease agents (antigens) and create antibodies to tag and remove these antigens

-- phagocytes are the white blood cell type that actually eats and destroys these antigens

Lymph Nodes – help filter bacteria and viruses in which WBC’s destroy. Located in the neck, arm and groin region.

White blood cell transfusion helps fight cancer in mice, science gets the go ahead to try on humans.

White blood cells

Cancer cell

The Muscular SystemPurpose: works with the skeletal and nervous system to produce movement, also helps to circulate blood through the human body and digested food.

-- muscle contractions can be voluntary or involuntary

Types of Muscles in the Human Body

-- Cardiac ex: heart

-- smooth ex: stomach

-- skeletal ex: triceps, biceps

Skeletal/striated muscles are made up of numerous muscle fibers or sarcomeres.  The sarcomeres are made up actin and myosin filaments.  Myosin filaments are thicker than the actin filaments, which is what gives the striated appearance.  These two fibers move back and forth across each other as the muscle contracts and relax.  The process of contraction is a complex one involving nerve stimulation of the actin and myosin filaments.  The key elements involved are sodium and calcium ions.  An imbalance or shortage of these ions can result in muscle fatigue and/or cramping.

The human body has about 650 muscles—we say “about” because there is some disagreement as to which muscles are separate and that results in different muscle totals. smallest muscle is the stapedius

located in the middle ear and is 1.27 mm long. It controls the tiniest bone in the body, the stapes or stirrup bone. The stapes and two other bones conduct sound vibrations through the middle ear.

Body WorldsExhibit of real organisms specially preserved to study the body systems

The Respiratory SystemPurpose: to provide the body with a fresh supply of oxygen for cellular respiration and remove the waste product carbon dioxide

Major Organs and Their Functions

Nose/Mouth – internal entry and exit point for air

Pharynx – serves as a passage way for both air and food at the back of the throat

Trachea – the “windpipe”, or what connects your pharynx to your lungs

-- a piece of skin, called the epiglottis, covers the trachea when you swallow, preventing food from entering your lungs

Bronchi – the two large passageways that lead from the trachea to your lungs (one for each lung)

-- the bronchi are further subdivided into bronchioles

-- eventually, the further subdivisions lead to tiny air sacs called alveoli

-- alveoli are in clusters, like grapes

-- capillaries surrounding each alveolus is where the exchange of gases with

the blood occurs

diaphragm is the muscle that causes

you to breath

-- hiccups are involuntary

contractions of the diaphragm

Image of the Respiratory System

Respiratory system of other animals

External and Internal gills

The Skeletal SystemPurpose: to provide structure and support to the body, protect vital organs and interact with muscles for movement.

Bones are where new blood cells are generated (in the marrow), and require the mineral calcium for strength

The Skeletal system includes bones, cartilage and ligaments.

-- femur- strongest bone in the body

-- patella- floating knee cap

exoskeletons

endoskeletons

The Digestive SystemPurpose: to convert food particles into simpler macromolecules that can be absorbed into the bloodstream and used by the body

Digestive System Animation click here

Major Organs and their Functions:

Mouth – to chew and grind up food

-- saliva also begins the chemical breakdown

Esophagus – pipe connecting mouth to stomach

Stomach – secretes an extraordinarily strong acid (pH = 2) that leads to breakdown of food

-- once the food is broken down in the stomach and mixed with digestive juices, it is called chyme

Pancreas – produces the hormone insulin that regulates blood sugar levels

-- also help neutralize stomach acid

Liver – produces bile, which breaks down fats in foods

Gallbladder – pouch-like organ that stores bile for future use to break down fats

Small Intestine – after digestion is complete, the chyme enters the small intestine where it is absorbed into the bloodstream

-- the chyme is propelled along by folded surfaces called villi, on the intestine

Large Intestine – removes water from the chyme and gets the waste ready for excretion

Rectum – solid (food) waste travels out of the body through the rectum

Types of DigestionMechanical – actual break down of food into smaller bits.

– Mastication –the chewing of food using the teeth. The food is broken down to smaller pieces and enables the chemicals in food to be released. These chemicals make digestion quicker and easier.

– Peristalsis – consecutive contractions of muscles found in the stomach. This enables the food particles to mix with enzymes and gastric juices.

Chemical- occurs when digestive enzymes combine with water to break down fat, carbohydrates and protein into smaller molecules which can be easily absorbed by cells.

Saliva, gastric juices (HCl acid), pancreatic juice, gall bladder and enzymes.

Site of Enzyme Origin

Enzyme Nutrient It Breacks Down

Product Of Enzyme Action

Place of Enzyme Action

Salivary Glands

Salivary Amylase

Carbohydrates-sugars

Simple Sugars

Mouth

Gastric glands

Pepsin Proteins Amino Acids Stomach

Liver Bile Fats/Lipids Emulsifide Fats

Small Intestine

Small Intestine

Maltase, Lactase, Sucrase

Carbohydrates

Simple sugars Small Intestine

Pancrease Trypsin, Lipase, Amylase

Proteins, Fats/Lipids, Carbohydrates

Amino acids, Glycerol/Fatty Acids, Simple Sugars

Small Intestine

Image of the Digestive System

Reproductive SystemPurpose- survival of the species. To produce the offspring, the reproductive system has four functions:

To produce egg and sperm cells To transport and sustain these cells To nurture the developing offspring To produce hormones

Reproductive OrgansFemale- Ovaries produce eggs (gametes) and estrogenMale-Testes produce sperm (gametes) and testosterone

Hormones aid in the maturation of the reproductive system, promote the development of sexual characteristics, and regulate the normal physiology of the reproductive system.

Other reproductive organs, ducts, and glands are used in transport and for sustaining the gametes and as well as nurturing the developing offspring. 

Binary fission

Budding

Cloning

Conjugation

The Endocrine SystemPurpose: to control growth, development, metabolism, reproduction and regulates other organ systems through the production and secretion of hormones

Major Organs

-- hypothalamus- controls body temp, hunger, thirst, fatigue, and circadian cycles-- pituitary gland- regulate growth, blood pressure, uterine contractions during childbirth, breast milk, sex organs, thyroid function, temp, etc

-- thyroid- controls how fast the body burns energy & makes proteins

-- adrenal glands- development and growth, affect our ability to deal with stress, and help to regulate kidney function

-- pancreas (sweet bread)- produce hormones such as insulin and digestive enzymes to break down food

-- testes- testosterone -- ovaries- estrogen and progesterone

The Nervous SystemPurpose: Controls sensory and motor functions, regulates behavior, maintains homeostasis and regulates other organ systems

Major Organs and Their Functions

Brain – control center of the body, where all processes are relayed through

-- consists of cerebrum (controls thought and senses) and cerebellum (controls motor functions)

Spinal Cord – sends instructions from the brain to the rest of the body and vice versa

-- any organism with a major nerve cord is classified as a chordate

Nerves – conduct impulses to muscle cells throughout the body

Diagram of a Nerve Cell

The Circulatory SystemPurpose: to transport nutrients, wastes, hormones and gases through out the organism

The Flow of Blood Through the Circulatory System (Click here)

Major Organs and Their Functions

Heart (muscle)–pumps blood through Arteries (oxygen rich) away from the heart and to the major organs of the body and Veins (oxygen poor) carry blood back to the heart away from the major organs of the body.

Capillaries – small blood vessels where gas exchange occurs

Blood – the cells that flow through the circulatory system

-- red blood cells contain hemoglobin, an iron-rich protein that carries oxygen

-- white blood cells function in the immune system

-- platelets help in blood clotting

Spleen – helps to filter out toxins in the blood and recycle old RBC’s

Image of the Circulatory System

Open circulatory system Closed circulatory system

Integumentary SystemPurpose- Protects against injury, infection, fluid loss and regulates body temperature

Major StructuresSkin -is our largest organ and aids as protection. Our eyelids have the thinnest skin, the soles of our feet the thickest.Hair –modified skin that aids in protection and regulate temperature. Nails -modified skin that aids in protection of tips from injury. Aid in picking up small objects, grasping, scratching and digging. Nails can be an indicator of a person's general health and illness often affects their growth.

The Excretory SystemPurpose: to rid the body of wastes, including excess water and salts

Major Organs and Their Functions

Kidneys – waste-laden blood enters the kidney and the kidney filters out urea, excess water and other waste products, which eventually travel out of the kidney as urine

-- eventually they travel through the ureter to the urinary bladder for temporary storage and out the urethra

Skin – sweat glands remove excess water and salts from the body

Lungs – expel the waste gas carbon dioxide

Image of the Excretory System