Human Anatomy and Physiology: Body systems

• Anatomy is the study of the structure of the body
• Physiology is the study of how the body functions

Human Body Systems

• The human body has multiple organ systems that work together
• The main systems are: integumentary, skeletal, muscular, nervous, endocrine, cardiovascular, lymphatic, respiratory, digestive, urinary, and reproductive
• The integumentary system (skin, hair, nails) provides protection, regulates temperature, and detects sensations
• The skeletal system (bones, joints) supports the body, protects organs, and provides a framework for movement
• The muscular system (skeletal muscles) enables movement, maintains posture, and generates heat
• The nervous system (brain, spinal cord, nerves) controls and coordinates body functions and responses
• The endocrine system (glands) secretes hormones to regulate various body functions
• The cardiovascular system (heart, blood vessels) transports blood, oxygen, and nutrients throughout the body
• The lymphatic system (lymph vessels, lymph nodes) returns fluids to the bloodstream and plays a role in immunity
• The respiratory system (lungs, airways) exchanges gases (oxygen and carbon dioxide) between the body and the environment
• The digestive system (stomach, intestines, liver, pancreas) breaks down food for absorption and eliminates waste
• The urinary system (kidneys, bladder) filters waste from the blood and regulates fluid balance
• The reproductive system (male and female reproductive organs) enables procreation

Cell Structure and Function

• The cell is the basic structural and functional unit of the body
• Major cell structures include the plasma membrane, cytoplasm, and nucleus
• The plasma membrane surrounds the cell and regulates the movement of substances in and out
• The cytoplasm is the gel-like substance within the cell that contains organelles
• The nucleus contains the cell's genetic material (DNA) and controls cell activities
• Organelles perform specific functions within the cell
• Mitochondria produce energy through cellular respiration
• Ribosomes synthesize proteins
• The endoplasmic reticulum (ER) is involved in protein and lipid synthesis
• The Golgi apparatus processes and packages proteins
• Lysosomes contain enzymes for breaking down cellular waste
• Cells perform various functions, including metabolism, growth, reproduction, and response to stimuli

Musculoskeletal Anatomy

• The musculoskeletal system consists of bones, joints, and muscles
• Bones provide support, protection, and a framework for movement
• Joints are the points where bones meet, allowing for movement
• Muscles attach to bones and contract to produce movement
• The skeleton is divided into the axial skeleton (skull, vertebral column, rib cage) and the appendicular skeleton (limbs, girdles)
• Bones are classified by shape: long, short, flat, irregular, and sesamoid
• Joints are classified by structure (fibrous, cartilaginous, synovial) and function (immovable, slightly movable, freely movable)
• Skeletal muscles are responsible for voluntary movement
• Muscles attach to bones via tendons
• Muscle contraction is initiated by nerve impulses
• Types of muscle tissue include skeletal, smooth, and cardiac

Cardiovascular System

• The cardiovascular system consists of the heart, blood vessels, and blood
• The heart is a muscular organ that pumps blood throughout the body
• Blood vessels include arteries, veins, and capillaries
• Arteries carry blood away from the heart
• Veins carry blood back to the heart
• Capillaries are small vessels where exchange of oxygen, nutrients, and waste occurs
• Blood transports oxygen, carbon dioxide, nutrients, hormones, and waste products
• The heart has four chambers: two atria and two ventricles
• Blood flows through the heart in a specific pathway: right atrium, right ventricle, pulmonary artery, lungs, pulmonary vein, left atrium, left ventricle, aorta
• The cardiac cycle consists of systole (contraction) and diastole (relaxation)
• Blood pressure is the force of blood against the walls of arteries
• The cardiovascular system plays a role in regulating body temperature and fluid balance

Nervous System Physiology

• The nervous system consists of the brain, spinal cord, and nerves
• It coordinates and controls body functions through electrical and chemical signals
• The nervous system has two main divisions: the central nervous system (CNS) and the peripheral nervous system (PNS)
• The CNS consists of the brain and spinal cord
• The PNS consists of nerves that connect the CNS to the rest of the body
• Neurons are the basic functional units of the nervous system
• Neurons transmit electrical signals called nerve impulses
• A neuron consists of a cell body, dendrites, and an axon
• Dendrites receive signals from other neurons
• The axon transmits signals to other neurons or cells
• Nerve impulses travel along the axon to the axon terminals
• Neurotransmitters are chemicals released at the synapse (junction between neurons) to transmit signals
• The brain is the control center of the nervous system
• The brain has different regions with specific functions: cerebrum, cerebellum, brainstem
• The cerebrum is responsible for higher-level functions like thinking and memory
• The cerebellum coordinates movement and balance
• The brainstem controls basic life functions like breathing and heart rate
• The spinal cord transmits signals between the brain and the body
• The PNS has two divisions: the somatic nervous system and the autonomic nervous system
• The somatic nervous system controls voluntary movements
• The autonomic nervous system controls involuntary functions like heart rate and digestion
• The autonomic nervous system has two branches: the sympathetic and parasympathetic
• The sympathetic nervous system prepares the body for "fight or flight" responses
• The parasympathetic nervous system promotes "rest and digest" functions