Body Systems

Levels of Organization:

Cell

  • Basic unit of all living things

  • Blood cells, nerve cells, bone cells

Tissue

  • Made up of cells to perform a specific activity

  • Muscles, nerves, epithelial and connective

Organ

  • Made up of tissues that work together to perform a specific activity

  • Ex. Heart, brain, skin

Organ System

  • Groups of two or more organs that work together to help maintain homeostasis in the body

  • Digestive, nervous, skeletal, endocrine

Organism

  • Entire living things that can carry out all basic life processes

  • Bacteria, amoeba, mushroom, palm tree, cow, human

Muscle Tissue

  • Contracts and Relaxes to move organs

  • Found throughout the body, not just in muscle system organs

  • Ex. biceps, abs, stomach, tongue, heart, veins, penis, vagina

Nerve Tissue

  • Sends and receives signals to and from organs.  

  • Senses signals internally and externally from the body

  • Ex. Brain, Nerves, Spinal Cord

  • 5 sensory organs: 

    • tongue

    • ears

    • nose

    • skin

    • eyes

Connective Tissue

  • Serves as support for organs

  • Connects organs

  • Strongest tissue in the body

  • Ex. Cartilage, bones, tendons, ligaments, glands, blood, lungs

Epithelial tissue

  • Lining of internal and external organs

  • Ex. Skin, Hair and Nails

Body Systems

Integumentary System

  • Main function: Protect other organs, like bones, muscles, and tissues

  • Temperature regulation

  • Elimination of waste products (through sweat)

  • Organs include: body hair, nails, skin

  • 3 layers make up the skin

    • Epidermis

    • Dermis

    • Hypodermis

  • The most common hair color is black, only 2% of the world is blonde

  • You will shed 40 lbs. of skin in a lifetime

  • Conditions that affect the system:

    • Vitiligo

    • Eczema

    • Acne

Skeletal System

  • Main function: to support, move, and protect the body

    • Produce blood cells

    • Store calcium

  • Organs include: bones, cartilage, tendons and ligaments

  • The outer layer of bones is compact and stiff.

    •  The inner part of the bone is spongy. 

    • The center of bones has bone marrow (red or yellow)

  • Osteoblasts are the cells that form and repair bones

  • Some problems the skeletal system may experience:

    • Whiplash

    • Osteoporosis

    • Arthritis

    • Scoliosis

  • The smallest bones in your body are found in your ear

Muscular System

  • Main function: To move the body

    • Protection

    • Maintain posture

  • Organs include muscles and tendons (sternocleidomastoid, gastrocnemius, trapezius, occipitofrontalis)

  • Three types of muscle tissue:

    • Visceral (smooth) – makes up organs like stomach, intestines, veins. Weak.

    • Cardiac – makes up the heart only. Cannot be controlled consciously

    • Skeletal – only muscle you can control by choice. Typical muscles to perform actions.

  • The only muscle that never tires out is the heart

  • Muscles make up 40% of your total body weight

  • Common problems with the muscular system: muscular dystrophy, muscle strains, fibromyalgia

Nervous System

  • Main function: To transmit signals throughout the body

    • can be voluntary or involuntary

  • Organs include:

    • Brain, spinal chord, nerves

    • Neurons (cells that release neurotransmitters)

    • Two parts:

      • Central Nervous System (CNS)

        • brain, spine

        • Command center where all information is transmitted

      • Peripheral Nervous System (PNS)

        • nerves

        • Pathways of information from around the body

Circulatory System

  • Main function: To carry gases and nutrients around the body

    • Healing

    • Regulate body temperature

  • Organs include:

    • Heart

    • blood vessels: arteries, veins, capillaries 

    •  blood

  • Arteries pump blood away from the heart

  • Veins pump blood toward the heart

  • Capillaries are the site of exchange (ex. oxygen and CO2)

  • When you are hot, your blood cells move to the ends of your body and expand

When you are cold, your blood cells shrink and move toward the center of your body

Respiratory System

  • Main function: Transfer oxygen from the air to blood and expel carbon dioxide

  • Organs include:

    • Lungs, nasal/oral cavity, trachea, diaphragm

  • Path of oxygen:

    • Enters through nose/mouth

    • Passes down Trachea

    • Enters lungs through bronchi (tube for each lung)

    • At the end of the bronchi there are many smaller tubes called bronchioles

    • O2 goes from bronchioles to alveoli where red blood cells take in the oxygen and release the CO2

Excretory System

  • Main function: To discharge waste and cleanse the body

    • Regulate water levels (hydration)

  • Organs include:

    • Urine:Kidneys, ureter, bladder, urethra

Accessory Organs: CO2:Lungs and Sweat: Skin

  • Kidneys remove waste (water, salt, other waste) from the blood

  • Urea is mixed with water in the bladder to create urine

  • Small amounts of urea get released into the bladder every 10-15 seconds

  • When the bladder is full, it sends signals to the brain, so that the urine can be released through the urethra

  • Common problems:

    • Kidney stones

    • Urinary tract infections (UTI)

    • Kidney failure

Digestive System

  • Main function: convert food into energy

    • take in food

    • break down food(saliva, chewing, acids)

    • absorb nutrients

    • move wasted material out of the body

  • Organs include:

    • Digestive Tract: mouth, esophagus, stomach, small/large intestines, rectum, anus

    • Accessory organs: liver, pancreas, gallbladder

  • Pathway of food:

    • Enters mouth

    • Travels down esophagus into stomach

    • Stomach breaks it down further

    • Small intestine absorbs nutrients

    • Large intestine removes water

    • Leftovers enter rectum and empty out through anus

  • Common problems: 

    • Heartburn

    • Ulcer

    • Colon Cancer

  • Females have a longer small intestine

  • You are always able to swallow your food, even when upside down

Endocrine System

  • Main function: produce hormones to maintain various functions

    • metabolism, growth, sexual function, sleep, and mood, blood sugar levels

  • Organs include:

    • pituitary gland, thyroid gland, adrenal gland, ovary/testes, pancreas, parathyroid, thymus, pineal gland

Immune System

  • Main function: protect the body against disease

  • Organs include:

    • lymph nodes, spleen, thymus, tonsils

  • Cells: white blood cells(t-cells and b-cells)

  • How your body fights infection:

    • Virus enters body. T-cells detect and alert body

    • White blood cells attack the virus first

    • B-cells make special antibodies to fight the virus

    • Virus is broken down and eliminated

    • Antibodies stay inside you in case you become reinfected