Overview of Human Body Systems

Anatomical Position and Body Planes

  • Anatomical Position: Standing upright, facing forward with arms at the sides and palms facing forward.

  • Body Planes:

    • Sagittal: Divides the body into left and right parts.

    • Midsagittal: Divides the body into equal left and right halves.

    • Coronal/Frontal: Divides the body into anterior (front) and posterior (back) parts.

    • Transverse/Horizontal: Divides the body into superior (upper) and inferior (lower) parts.

Directional Terms

  • Superior: Toward the head.

  • Inferior: Away from the head.

  • Anterior: Toward the front.

  • Posterior: Toward the back.

  • Medial: Toward the midline of the body.

  • Lateral: Away from the midline of the body.

  • Proximal: Closer to the point of attachment.

  • Distal: Farther from the point of attachment.

  • Superficial: Near the surface of the body.

  • Deep: Away from the surface of the body.

The Skeletal System: Functions

  • Provides Structure and Support: Forms the framework of the body, giving it shape and support.

  • Allows Muscle Attachment and Movement: Bones serve as points for muscle attachment, allowing for movement through a lever system.

  • Stores Minerals: Acts as a reservoir for calcium and phosphorus.

  • Produces Blood Cells: Red bone marrow produces red blood cells, white blood cells, and platelets through hematopoiesis.

The Skeletal System: Skull Bones

  • Cranium: Protects the brain.

  • Frontal Bone: Forms the forehead and roof of the eye orbits.

  • Parietal Bones: Form the top and sides of the cranium.

  • Occipital Bone: Contains foramen magnum where the spinal cord connects to the brain.

  • Temporal Bones: House ear structures and articulate with the mandible.

  • Maxillae: Upper jawbone forming part of the mouth and nasal cavity.

  • Mandible: Lower jawbone, allows for chewing.

The Skeletal System: Vertebral Column

  • Cervical Vertebrae: 7 vertebrae in the neck, support the head.

  • Thoracic Vertebrae: 12 vertebrae in the mid-back, attached to ribs.

  • Lumbar Vertebrae: 5 large vertebrae in the lower back.

  • Sacrum and Coccyx: Sacrum consists of 5 fused vertebrae; coccyx is 3-5 fused vertebrae.

The Skeletal System: Upper Body Bones

  • Ribs and Sternum: Protect thoracic cavity organs; sternum connects to ribs.

  • Humerus: Upper arm bone.

  • Radius and Ulna: Forearm bones; radius is lateral, ulna is medial.

  • Hand Bones: Carpals (8), metacarpals (5), phalanges (14).

The Skeletal System: Lower Body Bones

  • Pelvis: Supports body weight and protects reproductive organs.

  • Femur: Largest bone, connects hip to knee.

  • Patella: Kneecap, protects the knee joint.

  • Tibia and Fibula: Shin bones; tibia is larger and weight-bearing, fibula is smaller.

  • Foot Bones: Tarsals (7), metatarsals (5), phalanges (14).

Joints and Ligaments

  • Joint: Point where two bones meet, allowing movement.

  • Immovable Joints: Skull sutures (synarthroses).

  • Movable Joints: Shoulder and knee (diarthroses).

  • Ligaments: Connective tissues connecting bones, providing joint stability.

Skeletal System Disorders: Fractures

  • Open Fractures: Bone breaks and pierces the skin; higher infection risk.

    • Characteristics: Requires surgical intervention, may damage surrounding tissues.

  • Closed Fractures: Bone breaks but remains under skin; lower infection risk.

    • Characteristics: May require immobilization with a cast.

Scoliosis

  • Cause: Abnormal lateral curvature of the spine.

  • Symptoms: Uneven shoulders, back pain.

  • Diagnosis: Physical examination and X-rays.

  • Treatment: Bracing or surgery in severe cases.

Osteoarthritis and Osteoporosis

  • Osteoarthritis: Cartilage breakdown leading to joint pain and stiffness.

    • Treatment: Pain relief, physical therapy, joint replacement.

  • Osteoporosis: Loss of bone density causing weak bones.

    • Treatment: Calcium and Vitamin D, weight-bearing exercise.

Muscle System: Functions

  • Movement: Muscles contract to produce body movement.

  • Thermogenesis: Muscle contractions generate heat.

  • Posture Maintenance: Constant contractions maintain body position.

  • Protection of Organs: Muscles protect vital organs.

Types of Muscle Tissue

  • Cardiac Muscle: Striated, involuntary; heart.

  • Smooth Muscle: Non-striated, involuntary; internal organs.

  • Skeletal Muscle: Striated, voluntary; attached to bones.

Upper Body Muscles

  • Biceps Brachii: Flexes the elbow.

  • Triceps Brachii: Extends the elbow.

  • Trapezius: Moves the scapula.

  • Deltoid: Enables arm abduction.

Tendons and Muscle Disorders

  • Tendons: Connect muscles to bones; transmit force.

  • Muscle Disorders:

    • Tendinosis: Degeneration due to overuse.

    • Muscular Dystrophy: Genetic disorder causing weakness.

    • Strain: Overstretching of muscle fibers.

    • Spasms: Involuntary contractions causing pain.

Integumentary System: Functions

  • Protection: Barrier against infection.

  • Vitamin D Production: Synthesizes vitamin D from sunlight.

  • Sensory Perception: Contains receptors for touch, pain.

  • Temperature Regulation: Controls body temperature through sweat.

Layers of the Skin

  • Epidermis: Outer layer; protection.

  • Dermis: Middle layer; contains nerves and blood vessels.

  • Hypodermis: Inner layer; stores fat and cushions.

Integumentary Disorders

  • Acne: Clogged hair follicles causing blemishes.

  • Fungal Infections: Caused by fungi, results in scaly patches.

  • Skin Cancer: Abnormal growth of skin cells; includes melanoma.

Cardiovascular System: Functions

  • Transport Nutrients and Wastes: Carries nutrients to cells.

  • Temperature Regulation: Blood vessels regulate heat.

  • Gas Exchange: Delivers oxygen and removes carbon dioxide.

  • Hormone Distribution: Transports hormones to target tissues.

Structure of the Heart

  • Right Atrium: Receives deoxygenated blood via vena cava.

  • Right Ventricle: Pumps blood to lungs.

  • Left Atrium: Receives oxygenated blood from lungs.

  • Left Ventricle: Pumps oxygenated blood to body.

Blood Flow Through the Heart !!!!!!!

  1. Body to Right Atrium

  2. Right Atrium to Right Ventricle

  3. Right Ventricle to Lungs

  4. Lungs to Left Atrium

  5. Left Atrium to Left Ventricle

  6. Left Ventricle to Body

Blood Vessels

  • Arteries: Carry oxygen-rich blood from the heart.

  • Capillaries: Site of gas and nutrient exchange.

  • Veins: Carry oxygen-poor blood back to the heart.

Cardiovascular Disorders

  • Atherosclerosis: Plaque buildup causing narrowed arteries.

  • Hypertension: High blood pressure affecting organs.

  • Myocardial Infarction: Heart attack due to blood flow blockage.

Respiratory System: Functions

  • Gas Exchange: Supplies oxygen, removes carbon dioxide.

  • Air Conditioning: Warms and filters air.

  • Sound Production: The larynx produces sound.

Respiratory System Structures

  • Nasal Cavity: Filters, warms air.

  • Pharynx and Larynx: Passageway for air; produce sound.

  • Bronchi and Alveoli: Distribute air; site of gas exchange.

Respiratory Disorders

  • Pneumonia: Infection causing fluid in lungs.

  • Asthma: Airways inflamed and narrow.

  • Lung Cancer: Abnormal cell growth in lungs.

Immune System: Structure and Function

  • Function: Protects body from infections.

  • Key Structures:

    • Tonsils: Trap pathogens.

    • Lymph Nodes: Filter harmful substances.

    • Spleen: Filters blood.

    • White Blood Cells: Attack pathogens.

Nervous System: Functions

  • Control and Coordination: Supervises body functions.

  • Signal Transmission: Sensory receptors detect stimuli; signals are transmitted to the CNS (Central Nervous System).

Neuron Structure

  • Cell Body: Contains the nucleus.

  • Dendrites: Receive signals.

  • Axon: Transmits impulses away from the cell body.

Nervous System Disorders

  • Meningitis: Inflammation of meninges.

  • Concussion: Brain injury from trauma.

  • Stroke: Due to ischemic or hemorrhagic causes.

Special Senses

  • Smell: Detected by chemoreceptors in the nose.

  • Taste: Detected by taste buds on the tongue.

  • Hearing and Balance: Detected by mechanoreceptors in the ear.

  • Vision: Detected by photoreceptors in the retina.

Endocrine System: Functions

  • Regulates Metabolism: Control rate of energy conversion.

  • Controls Growth and Development: Influences physical growth.

  • Maintains Homeostasis: Regulates internal conditions.

Major Endocrine Glands and Hormones

  • Pituitary: Growth hormone regulates growth.

  • Thyroid: Thyroxine controls metabolism.

  • Pancreas: Insulin regulates blood sugar.

Digestive System: Functions

  • Ingestion: Intake of food and liquids.

  • Digestion: Breakdown of food.

  • Absorption: Nutrients pass into the bloodstream.

  • Excretion: Elimination of waste products.

Digestive System Disorders

  • Crohn's Disease: Autoimmune cause; treated with medications.

  • Appendicitis: Infection leading to surgical removal.

Urinary and Reproductive Systems

  • Urinary System: Regulation of blood volume and waste excretion. Key organs include kidneys, ureters, bladder.

  • Reproductive System: Production of gametes; hormonal function. Disorders include endometriosis and STIs.