Human Body Systems The Human Body The organs

Human Body Systems

The Human Body The organs of the body work together in organ systems to perform specific functions. Organ systems are often connected and work together to allow the body to function and to maintain homeostasis (a stable internal environment of the body. )

Circulatory System Includes the Heart, blood, and blood vessels.

The purpose of the circulatory system is to transport oxygen and nutrients to the cells, and pick up carbon dioxide and other waste.

Blood includes: Red Blood Cells - contain hemoglobin molecules which carry oxygen White Blood Cells – fight disease Platelets – cell fragments that help blood clot. Plasma – liquid part of blood

The heart has 4 chambers. The upper chambers are the atria (atrium is singular) and the lower chambers are the ventricles.

Blood Vessels: Arteries carry blood away from the heart. Veins carry blood back to the heart. Capillaries – tiny vessels that allow for nutrient and gas exchange.

Digestive system Includes the mouth, esophagus, stomach, small and large intestine, liver, pancreas.

The digestive system uses enzymes to break down food so that it can be carried to the cells and used to make energy (ATP) and then remove the wastes.

Digestion begins in the mouth with chewing and the enzymes in saliva.

After the food is swallowed it travels through the esophagus to the stomach where the enzyme pepsin breaks down proteins.

Food then enters the small intestine which is lined with tiny villi that absorb nutrients. The villi are the link between the digestive system and the circulatory system.

Excess water is absorbed in the large intestine. The large intestine contains the beneficial form of Escherichia coli (E. coli ) a bacteria that helps you digest your food. Large intestine

Nervous System Brain, spinal cord, nerves: ◦ Control the other systems of the body. Works with other systems to maintain homeostasis.

The basic unit of structure and function in the nervous system is the neuron, or nerve cell.

Chemicals called neurotransmitters cross a gap called a synapse to carry messages from one neuron to another.

The nervous system can be divided into the central and peripheral nervous systems. The central nervous system includes the brain and spinal cord.

The peripheral nervous system carries impulses from the body to the central nervous system.

Parts of the brain: Cerebrum – divided into 2 halves. Controls your conscious activities, intelligence, memory, language, muscle movement, and senses. Cerebellum – balance, posture and coordination. Brain stem – made up of the medulla oblongata, pons, and midbrain. The medula oblongata controls involuntary activities such as breathing and heart rate.

cerebrum cerebellum brain stem

The medulla oblongata (part of the brain stem) reacts to increased levels of CO 2 in your blood stream, stimulating the respiratory system to increase the rate of breathing.

Endocrine System Includes the pituitary, ovaries, testis, pancreas, adrenal glands and thyroid

The nervous system works closely with the endocrine system. The endocrine system is a system of ductless glands that produce hormones that circulate in the blood stream and controls the other body systems.

Endocrine Glands and Hormones Pancreas – secretes insulin which regulates blood sugar levels. Pituitary – Master gland – secretes growth hormone Thyroid – secretes thyroxin which regulates metabolism. Adrenal glands – produce hormones to prepare body for “fight or flight” Testes and ovaries – reproductive hormones

Reproductive System Ovaries, fallopian tubes, uterus, vagina (females) testis, seminiferous tubules, vas deferens, penis (males)

Meiosis produces gametes in ovaries and testis. The remainder of the system either deliver them, or protect a developing fetus until birth.

Integumentary System Serves as a barrier against infection and injury Regulates body temperature Removes waste products Protection against UV rays

Types of tissue in the integumentary system Skin Hair Nails

Skin ◦ Epidermis- outer layer of the skin ◦ Dermis- inner layer of the skin Hair ◦ Protects the scalp from UV light ◦ Prevents dirt and other particles from entering the body ◦ Hair follicles- tube-like pockets of epidermal cells Nails ◦ Protects the tips of the fingers and toes ◦ Fingernails grow more rapidly than toenails

Skeletal System Bones, ligaments, cartilage

Functions of the skeletal system Supports the body ◦ Bones act as framework for the body Protects internal organs ◦ Ex. Skull and the ribcage Provides movement ◦ Bones act as levers Stores mineral reserves ◦ Bone marrow Provides site for blood cell formation ◦ In the bone marrow

Divisions of the Skeletal Skeleton Axial Skeleton ◦ Skull ◦ Sternum ◦ Ribs ◦ Vertebral column

Divisions of the Skeletal System Appendicular Skeleton Arm bones ◦ ◦ ◦ ◦ ◦ Clavicle- collar bone Scapula- shoulder blade Humerus- upper arm bone Radius- lower arm bone (thumb side) Ulna- lower arm bone (pinky side) Pelvis- hip bone Carpals- wrist bones Metacarpals- hand bones Phalanges- finger bones Leg Bones ◦ Pelvis-hip bone ◦ Femur- upper leg bone ◦ Tibia –lower leg bone (big toe side) ◦ Fibula- lower leg bone (little toe side) ◦ Tarsals- ankle bones ◦ Metatarsals- foot bone ◦ Phalanges- toe bones

Structure of Bone • Bones are living cells that are surrounded by calcium salts. • Periosteum-tough layer of connective tissue • Haversian canals- tubes in the bone that contain blood and nerve supply • Osteocytes- newly formed bone cells • Osteoblasts- bone forming cells • Bone marrow- soft tissue inside the cavity of a bone -yellow marrow- made up of stored fat cells -red marrow- produces red blood cells, white blood cells, and platelets

Types of Joints (where bones meet) Ball-and-socket joint ◦ Shoulder Hinge Joint ◦ Elbow, knee Pivot Joint ◦ Between radius and ulna Gliding ◦ Wrists and ankles

The Respiratory System includes: Mouth and nose Trachea – windpipe Bronchial tubes – from trachea to lungs Lungs – made up of tiny air sacs called alveoli.

The purpose of the respiratory system is to take in oxygen and release carbon dioxide.

Alveoli – tiny air sacs in the lungs where gases are exchanged with the bloodstream.

The diaphragm is a muscle that is important in breathing.

Tiny hairs called cilia line the air passages. Mucus traps particles and the cilia beat upward to keep the particles out of the lungs.

Muscular System Includes the muscles of the muscular system, digestive system, and heart

3 types of muscle tissue: 1. Smooth 2. Skeletal 3. Cardiac

Smooth Muscle ◦ Moves food through the digestive tract (perstalsis) ◦ Controls blood flow in the circulatory system ◦ Decreases size of pupils in bright light

Smooth muscle lines the organs of the digestive system such as the intestines.

Skeletal Muscle ◦ Produces voluntary movement Found attached to bones Ex. Biceps

Cardiac muscle makes up the heart.

Cardiac muscle Cardiac Muscle ◦ Pumps blood through body

Muscle cells that are working will sometimes run out of the oxygen required for aerobic respiration. Muscle cells can make small amounts of energy without oxygen (anaerobic respiration). When muscle cells make energy (ATP) without oxygen they produce lactic acid. Lactic acid makes your muscles sore.

Excretory System Includes the kidney, ureter, bladder, urethra : Main function: Takes nitrogenous waste from the blood stream for removal from the body.

Immune System Includes the white blood cells (lymphocytes including T-cells and Bcells which make antibodies), lymph nodes, spleen, tonsils. Main function: To fight infections.