Systems of the Body

THE NERVOUS SYSTEM FUNCTION: The nervous system controls & coordinates everything in the body. This includes all movement and all of the activities of the organs & organ systems.

MAJOR PARTS OF THE NERVOUS SYSTEM Brain: The controls center of the nervous system, and the whole body Spinal cord: Carries messages to and from the brain. Neurons (nerves) are the special cells that carry the messages through the body.

A neuron is long and thin to send messages through the body The nervous system sends electrical signals throughout the body. A signal travels through several neurons to the brain. The brain then sends messages back out to the rest of the body.

Brain Spinal Cord Nerves

THE CIRCULATORY SYSTEM: Function: The circulatory system & respiratory system work together to supply cells with the oxygen and nutrients they need to stay alive.

The Main Parts: 1. The heart Atria: 2 upper chambers, receive blood from the body Ventricles: 2 lower chambers, pump blood out of heart Valves: Regulate the flow of blood through the heart

2. Blood vessels: Arteries: Carry oxygenated blood to the heart Veins: Carry deoxygenated blood to the heart Capillaries: The smallest, bring nutrients & oxygen to the tissues & absorb carbon dioxide & other waste products from them

3. Blood: Red blood cells: Contain hemoglobin & carry oxygen White blood cells: Infection fighters Platelets: Clot blood Plasma: The liquid part of blood

The Flow of Blood Through the Body: Heart  Arteries  Capillaries  Veins  back to heart Diagram the Flow of Blood:

THE RESPIRATORY SYSTEM Function: The basic function of the human respiratory system is the exchange of oxygen & carbon dioxide between the blood, air and tissues. In addition, air entering the respiratory system is warmed, moistened & cleaned before it enters the lungs. Main Parts: Nose (& mouth): air enters here Pharynx: serves as a passageway for both AIR & food Epiglottis covers the entrance to the trachea when you swallow (so food does not go into lungs

Define: 1. Gas exchange: Oxygen diffuses into the blood & carbon dioxide diffuses from the blood out into the lung Breathing: The taking in of oxygen and release of carbon dioxide waste into the air Diaphragm: Muscle that controls breathing by moving up & down

Larynx: contains two elastic folds of tissue called vocal cords Trachea: also known as the windpipe Bronchi: two large passageways in the chest cavity, each bronchus leads into one the lungs Alveoli of lungs: tiny air sacs (like grapes) where gas is exchanged

Flow of air through the body: Nose Trachea  Bronchi  Bronchioles  Alveoli of the lungs

THE MUSCULAR SYSTEM FUNCTIONS: Muscle allow organs & bones of the body to move. The fibers that make up muscle, “contract”. The contraction makes the whole muscle shorter which allows them to move organs and bones.

3 TYPES OF MUSCLE 1. Skeletal: Attaches to bone & allows for movement 2. Smooth: Found in the walls of the stomach, intestines & blood vessels. Helps materials move through these structures 3. Cardiac: Makes the heart beat to send blood to the body.

HOW DO MUSCLES MOVE BONES? Muscles contract and cause bones to move. Tendon: Attaches a muscle to a bone Muscles work in pairs to cause movement: Ex: Bicep contracts & tricep relaxes  arm bends Bicep relaxes & tricep contracts  arm straightens

THE SKELETAL SYSTEM Functions: - supports the body - protects the organs - allows the body to move - makes blood cells Parts of the skeletal system: - bones - ligaments - tendons - cartilage

There are 206 bones in the human body. Bones are living tissue that grow and need blood. Bones have blood vessels inside of them and are made of cells Types of Bone Tissue: 1. Compact: Layer of hard bone that covers all bone 2. Spongy: Surrounded by the compact bone, it has many holes & spaces in it. Makes bones lighter. 3. Bone marrow: Soft tissue inside of bones makes blood cells

WHAT ARE JOINTS? A joint is where 2 or more bones meet & allow for movement

Joints are held together by a tough band of tissue called a ligament Tough & flexible cartilage might cover the ends of a bone to allow for smooth movement between bones

THE DIGESTIVE SYSTEM: Function: The digestive system converts food into simpler molecules that can be used by the cells of the body. The Parts of the Digestive System: 1. Key organs Mouth – food is chewed & mashed into paste and salivary glands secrete saliva which contains enzymes

Esophagus Muscular tube that contracts, pushing food into the stomach Stomach Muscular sac that churns, continuing the breakdown of food mechanically & chemically with enzymes Small Intestine long tube where most of the nutrient molecules are absorbed into cells Large Intestine Removes water from undigested food material. Also called the colon

Accessory Organs Pancreas Secretes hormones to control blood sugar (insulin) and enzymes to digest starch, fat, protein. Liver Produces bile which dissolves fat Gall bladder Stores bile before entering small intestine

Wall of small intestine Define: Mechanical digestion: Physical breakdown of food into smaller pieces by the teeth & churning stomach Chemical digestion: Enzymes chemically break food into smaller pieces in the mouth, stomach & small intestine Villi: Finger-like projections in the small intestine which increase the surface area so more nutrients can be absorbed Wall of small intestine

THE EXCRETORY SYSTEM: Function: The basic function of the human excretory system is the removal of waste from the cells and body. The skin excretes excess water and salts in the form of sweat. The lungs excrete carbon dioxide. The kidneys play a major role in excretion and remove waste products from the blood, maintain blood pH and regulate the water content of the blood and, therefore homeostasis.

THE MAIN PARTS: Kidneys = located on either side of the backbone and partially protected by the ribcage Blood enters the kidney and is cleaned and filtered. Urea (a toxic substance), excess salts, and water are removed from the blood and form urine. Once filtered, clean blood leaves the kidney and returns to circulation.

Nephrons = the functional, blood-filtering units of the kidney Ureters= 2 tubes, one leaving each kidney, carry urine to the urinary bladder Bladder= a saclike organ where urine is stored before being excreted Urethra= a tube that carries urine form the bladder & releases it from the body

DEFINE: Urea = Nitrogen containing waste made by the body Dialysis = Blood is removed from the body, cleaned by a machine & then returned to the body UREA REMOVAL FROM THE BODY: Kidneys  Ureter Bladder  Urethra released from body

THE REPRODUCTIVE SYSTEMS: The main function of the reproductive systems is to make egg and sperm cells which will combine to make a zygote (offspring)

Male Reproduction The function of the male reproductive system is to produce and deliver sperm. Sperm are made in the testes through the process of meiosis. In human males, sperm are haploid & have 23 chromosomes

Male Reproductive System Urinary bladder Vas deferens Pubic bone Seminal vesicle Urethra Rectum Penis Prostate gland Epididymis Bulbourethral gland Testis Scrotum

Female Reproductive system The functions of the female reproductive system include: To produce eggs To receive sperm Provide an environment that a baby can develop in

How are eggs produced & released in females? ovaries: 2 ovaries are where eggs are made through meiosis. 1 egg is released each month called ovulation fallopian tube: tube the egg travels through one it is released from the ovary. (also called oviduct) there are 2 fallopian tubes. uterus: fist sized organ where an embryo grows. vagina: passageway to the outside of the body - baby is born through this passageway and sperm are deposited here

cervix: small opening at the bottom of the uterus which leads into the vagina. Opens when a baby is born. Otherwise small so menstrual blood can exit the body. If a successful pregnancy is to occur, the egg must be fertilized by the sperm in the fallopian tube/oviduct. The fertilized egg is called a zygote and must then implant into the uterus, where it will develop for 9 month If fertilization hasn’t occurred, the egg then travels into the uterus, through the cervix and into the vagina and out the body.