Human Body Systems Overview

Levels of Organization

• Cells are the smallest units of the human body
• Tissues are groups of cells
• Organs are groups of tissues
• Organ systems are groups of organs
• Organisms are complex beings made of organ systems

Organ Systems and Functions

• Integumentary System: Forms external body covering (skin, hair, fingernails), waterproofs the body, cushions/protects deeper tissue, helps regulate body temperature. Vitamin D production.
• Skeletal System: Consists of bones, cartilages, ligaments, and joints. Provides muscle attachment, protects organs, site of blood cell formation, stores minerals.
• Muscular System: Skeletal muscles contract/shorten to produce movement of bones.
• Nervous System: Consists of brain, spinal cord, nerves, and sensory receptors. Fast-acting control system responds to internal/external stimuli. Central nervous assesses information and activates effectors (muscles/glands).
  • Endocrine System: Secretes hormones into the blood. Controls body functions including growth and reproduction, and nutrient use.
  • Cardiovascular System: Includes heart and blood vessels; pumps blood, transports blood to tissues, carries oxygen and carbon dioxide, and hormones. Blood also contains white blood cells for immunity.
  • Lymphatic System: Compliments cardiovascular system. Returns leaked fluids back to bloodstream, cleanses blood, and houses white blood cells involved in immunity.
  • Respiratory System: Includes nose, pharynx, larynx, trachea, bronchi, and lungs. Exchanges gases with the blood (supplies body with oxygen, removes carbon dioxide).
  • Digestive System: Includes mouth, esophagus, stomach, intestines, and accessory organs. Breaks down food/absorbs nutrients into blood, eliminates indigestible material.
  • Urinary System: Includes kidneys, ureters, bladder, and urethra. Eliminates waste, maintains acid-base balance, regulates water and electrolyte balance, regulates blood pressure.
  • Reproductive System: Males (testes, scrotum, accessory glands, duct system); Females (ovaries, uterine tubes, uterus).

Anatomical Position

• Standing upright, face forward, arms at sides, palms forward, feet parallel
• Standard for anatomical descriptions

Directional Terms

• Superior/Cranial/Cephalic: Towards the head, upper part of a structure/body
• Inferior/Caudal: Away from the head, toward the lower part of a structure/body
• Anterior/Ventral: Towards the front of the body
• Posterior/Dorsal: Towards the back of the body
• Medial: Towards the midline of the body (inner side)
• Lateral: Away from the midline of the body (outer side)
• Proximal: Closer to the origin of a body part or point of attachment
• Distal: Farther from the origin of a body part or point of attachment

Body Cavities

• Dorsal: -Cranial cavity (holds brain), -Spinal cavity (holds spinal cord)
• Ventral: -Thoracic cavity (heart, lungs, other organs; in the chest) -Abdominopelvic cavity (superior abdominal cavity contains stomach, liver, and other organs; inferior pelvic cavity contains reproductive organs, bladder, and rectum)

Positive and Negative Feedback Loops

• Positive: amplifies an effect (childbirth)
• Negative: reverses a deviation from normal range (blood pressure regulation)

Types of Energy

• Mechanical: associated with motion/position
• Thermal: associated with temperature
• Chemical: stored in bonds of atoms/molecules
• Electrical: carried by electrical current
• Nuclear: stored in an atom's nucleus
• Radiant: travels in waves (visible light)

Substances In Living Organisms

• Oxygen
• Carbon
• Hydrogen
• Nitrogen

Body Planes and Lines

• Sagittal: divides body into left and right
• Frontal/Coronal: divides body into front and back
• Transverse/Horizontal: divides body into top and bottom
• Median/Midsagittal: vertical plane through the midline of the body

Body Regions/Quadrants

• Right upper/lower quadrant (RUQ, RLQ)
• Left upper/lower quadrant (LUQ, LLQ)
• Specific body regions are further depicted on page 5.

Types of Bonds

• Ionic: attraction between oppositely charged ions.
• Covalent: sharing of electrons between atoms (polar or nonpolar).
• Hydrogen bonds: weak bonds.

Hydrolysis

• Chemical reaction breaking down compounds by adding water
  • Important for digestion and metabolism

Organic Compounds

• Contain carbon atoms.

pH Scale

• 0-6: acidic
• 7: neutral
• 8-14: basic. Human blood pH is 7.

Carbohydrates

• Monosaccharides: Single chain or ring structure (glucose, fructose, galactose)
• Disaccharides: Two monosaccharides linked (sucrose, maltose, lactose)
• Polysaccharides: Many monosaccharides linked (starch, glycogen)

Nucleic Acids

• DNA: Deoxyribonucleic acid - genetic material.
• Contains deoxyribose, bases adenine, thymine, cytosine and guanine.
• RNA: Ribonucleic acid- carries out DNA’s instructions.
• Contains ribose, bases adenine, uracil, cytosine, and guanine.

Phospholipids

• Lipids, two fatty acid chains and a polar head.
• Hydrophobic (water-fearing) fatty acid tails and hydrophilic (water loving) polar heads. Form cell membranes.

Plasma Membranes

• Selectively permeable barrier. Allows liquids/gases to pass through

Cells Division and Reproduction

• DNA Replication: Process where genetic material duplicates for cell division.
• Transcription: Copying of DNA’s base sequence into mRNA.
• Translation: Converting mRNA sequence to amino acid sequence to create proteins.
• Protein Synthesis: Process where cells create proteins.
  • Mitosis: Process of cell division resulting in two identical daughter cells.

Mutations

• Changes in DNA sequence
• Can affect characteristics/traits.

Types of Tissues

• Epithelial (epithelium): Covers body surfaces, lines cavities. Many types.

Types of Muscle Tissues

• Skeletal: Attached to skeleton, produces voluntary movement.
• Cardiac: Found only in the heart. Pumps blood.
• Smooth: Involuntary. Found in walls of organs; moves substances across internal channels and involved in digestion and breathing.

Types of Bone Tissues

• Compact: Dense, smooth, homogeneous
• Spongy: Small needlelike pieces of bone, many open spaces

Parts of a Long Bone

• Diaphysis/Shaft: Length
• Epiphysis/Ends: Spongy Bone
• Periosteum: Outer covering, fibrous membrane.

• Endosteum: Inner lining, connective tissue.
• Medullary cavity: Marrow-filled cavity (contains yellow marrow and Red Marrow (blood cell formation).
• Articular cartilage: Hyaline cartilaginous covering, reduces friction between bones at joints.

Types of Fractures

• Closed (simple): does not break the skin.
• Open (compound): breaks the skin.

Bone Fracture Repair

• Stages involving hematoma, fibrocartilage callus, bony callus, and bone remodeling.

Types of Joints

• Fibrous: Immobile or slightly movable (sutures, gomphoses, syndesmoses).
• Cartilaginous: Immovable or slightly movable ( synchrondroses, symphyses).
• Synovial: Freely moveable (e.g., hinge, ball-and-socket).

Parts and Functions of Hair

• Hair follicle: contains the hair root, bulb, matrix where hair grows.
• Medulla: central core
• Cortex: surrounding the medulla
• Cuticle: outermost layer.
• Melanocytes: produce melanin (pigment, giving color to hair).
• Arrector pili muscles/attach to follicles: cause hair to stand on end (goosebumps)

Tissues and Structure of the skin.

The epidermis is summarized as: basale, spinosum, granulosum, lucidum (optional) and corneum.

Types of Bones

Bone is categorized as: long, flat, short and irregular.

• Compact bone: Dense and smooth, homogeneous.
• Spongy bone - Small needlelike pieces of bone, many open spaces.

Parts of a Nail

• Free edge: outermost part you see.
• Nail body: visible attached portion.

Skeletal System Functions

• Support: framework
• Protection: enclosing organs and structures.
• Movement: Lever system for muscles.
• Mineral storage: reservoir for calcium and phosphorous.
• Blood cell formation: hematopoiesis in red marrow.

Additional Topics

• Homeostasis: Maintenance of relatively stable internal conditions. Critical for survival.
• Vertebral Curves: Primary (present at birth) and secondary curves (develop after birth).
• Pelvic Differences (male/female): Puberty impacts development.
• Osteoporosis: Bone-thinning disease, impacting older adults, often due to lack of estrogen.
• Rickets: preventable disease, causing softened and weakened bones in children often due to vitamin D/phosphorus deficiency.
• Bone Growth: Ossification and bone growth/repair.
• Importance of Anatomical Position: Crucial for communication/clarity in medical terminology.
• Types of Burns/Healing: Epidermal damage at different degrees, affects speed of recovery.
• Hyoid Bone: Unique among the body's bones.
• Other Additional Topics: Some topics such as types of fractures, spinal regions and details of the skeleton are covered earlier in these notes.
• Details/Examples: Some information and examples that are found in the larger text are included (e.g. the different tissues that form the skeletal system, functions and example of muscle types, skeletal, respiratory, digestive, urinary or reproductive systems.)

Explore the levels of organization within the human body, from cells to organisms. Learn about the major organ systems such as the integumentary, skeletal, muscular, and nervous systems, along with their functions. This quiz will help reinforce your understanding of the complexities of human biology.