Human Body Systems Part 1

Remember… All systems must work together in order to correlate all bodily functions Each body system is dependent upon on all others, however, some work more closely together than others!

Organization Cells  tissues  organs  organ systems  organism! The human body consists of 11 different organ systems that work together to maintain homeostasis

Maintaining Homeostasis We must keep internal conditions relatively constant Blood pressure (120/70), heart rate ( bpm), blood sugar levels, body temp (37 o C) We have feedback mechanisms to help keep these levels constant Positive – turns on response and amplifies Contractions and labor Negative – turns on and turns back off Temperature control, blood glucose levels, heart rate and respiration Most common Also called feedback inhibition

Integumentary System Skin system! Also includes hair, nails, and glands (secrete oils and sweat) Protects from invaders, helps regulate temp and water balance, removes wastes (sweat), and protects from UV rays

Skeletal System Supports the body and works closely with the muscular system for movement Protects internal organs New blood cells are produced in bone marrow – the soft tissue inside some bones Consists of bones (206) and cartilage (connective tissue)

Muscular System MOVEMENT!!! Works closely with nerves and bones to allow the body parts to move Types of muscle tissue Skeletal – attached to bones; striated (voluntary) Smooth – stomach, vessels, intestines (involuntary) Cardiac – heart, striated

Muscle Tissues

Muscle Contraction Occurs when thin filaments (actin) slide over thick filaments (myosin) Requires a lot of ATP  ENERGY!!! Involves a signal from neurons and neurotransmitters (chemical signals)

Nervous System Receives and transmits messages throughout the body Controls and coordinates bodily functions Allows for senses and response to stimuli

Neuron A specialized nerve cell Dendrites – receive messages from previous neuron Cell body – contains nucleus Axons – carry message “away” to next neuron Have insulation called myelin sheath Synapse – space between axon of one neuron and dendrites of another

Nerve Impulse Messages are carried between neurons via action potentials (electrical impulses) and neurotransmitters (chemical messengers)

Nervous System Central Nervous System (CNS) – Brain and spinal cord Control center Reflexes Peripheral Nervous System (PNS) – all other nerves Sensory (senses) and motor (movement) divisions Motor has somatic division (voluntary) and autonomic division (involuntary)

Circulatory System Also called cardiovascular system TRANSPORT system Moves oxygen, carbon dioxide, sugars, wastes, etc. all throughout the body Works really closely with the respiratory system to deliver oxygen and with the excretory system to rid of wastes Includes heart, vessels, and blood

Circulation Arteries – carry blood from heart to the body (have O 2 ) Branch into smaller arterioles Veins – carry blood from body back to heart (little O 2 ) Branch into smaller venules Capillaries – small vessels where materials are exchanged between blood and tissues

The Heart 2 atria – receive blood 2 ventricles – pump blood One way blood flow: right ventricle  pulmonary arteries to lungs  back to heart through pulmonary veins to left atrium  left ventricle and out aorta to body  back into right atrium through superior and inferior vena cava  right ventricle

Lymphatic System Network of vessels and nodes, thymus and spleen Collects fluid lost from blood and returns it to the circulatory system Lymph nodes filter microorganisms Vessels are also important for nutrient absorption

Respiratory System Responsible for exchange of oxygen and carbon dioxide between blood, air, and tissues Breathe in through nose and mouth  pharynx  trachea  lungs (bronchi to bronchioles to alveoli) Tiny airs sacs called alveoli provide a large surface area for gas exchange