Introduction to Human Anatomy & Physiology
Chapter 1: Introduction to Human Body
Difference Between Anatomy & Physiology
Anatomy is the study of the body’s structures.
Physiology is the study of how those structures work (their function).
Levels of Organization of the Body
- Chemical
- Cellular
- Tissue
- Organ
- Organ Systems
- Organismal
Homeostasis
Homeostasis is the maintenance of a relatively constant internal environment within normal limits. It’s a state of dynamic equilibrium.
How is Homeostasis Maintained?
- Homeostatic control mechanisms
- Mostly negative feedback
Components of a Homeostatic Control Mechanism
- Receptors
- Control center
- Effectors
Major Body Cavities
- Cranial cavity
- Vertebral canal
- Thoracic cavity
- Abdominopelvic cavity
Membranes (According to Associated Organs)
- Pericardium
- Pleura
- Peritoneum
Parietal Membrane
Lines the body cavity.
Visceral Membrane
Covers the organ.
Membranes Surrounding Organs
- Visceral pericardium
- Visceral pleura
- Visceral peritoneum
Membranes Lining Cavities
- Parietal pericardium
- Parietal pleura
- Parietal peritoneum
Anatomical Position
Standing erect, face forward, arms at sides, palms facing forward.
Planes
- Sagittal
- Transverse
- Coronal
Chapter 2: Chemistry of Life
Atoms
Atoms are the smallest complete units of elements.
Structure of an Atom
- Central nucleus, containing protons and neutrons.
- One or more electrons constantly moving around the nucleus.
What Determines the Chemical Behavior of an Atom?
The electrons in its outer shell.
Ions
An ion is an atom that has gained or lost an electron and become electrically charged.
Ionic Bond
An ionic bond is a type of chemical bond between atoms in which oppositely charged ions are attracted to each other.
Covalent Bond
A covalent bond is a type of chemical bond between atoms in which electrons are shared.
Polar Molecule
- A molecule that is covalently bonded, but the electrons are not shared equally.
- Results in one end of the molecule being slightly negative and the other end being slightly positive.
Acid
An acid is a compound that releases H+ (hydrogen ions) when dissolved in water.
Base
A base is a compound that releases OH- (hydroxide ions) when dissolved in water.
pH Scale
The pH scale measures hydrogen ion concentration.
High pH
Represents a basic solution.
Low pH
Represents an acidic solution.
Organic Compound
An organic compound is a compound that contains carbon.
Important Inorganic Substances
- Water
- Oxygen
- Carbon dioxide
- Salts
Important Organic Substances
- Carbohydrates
- Lipids
- Proteins
- Nucleic acids
Building Blocks
- Carbohydrates -> Monosaccharides (simple sugars)
- Lipids -> Glycerol, fatty acids, phosphate groups
- Proteins -> Amino acids
- Nucleic acids -> Nucleotides
Chapter 6: Integumentary System
Functions of Skin
- Temperature regulation
- Protection of underlying tissues
- Barrier between internal and external environments
- Houses sensory receptors
- Synthesizes certain chemicals (e.g., vitamin D)
Layers of Skin
Epidermis & Dermis
Layer Deep to the Dermis
Hypodermis or subcutaneous layer
Tissue of the Epidermis
Stratified squamous epithelium
Deepest Layer of the Epidermis
Stratum basale
Significance: Close to blood and nutrient supply, cells divide and grow, pushing older cells toward the surface.
What Happens to Dying Epidermal Cells?
- They become keratinized (cells harden, becoming tough and waterproof).
- Why do they die? Older cells get pushed farther from the blood supply.
Melanocytes
- Cells that secrete the pigment melanin (amount produced depends on genetics and sun exposure).
- Location: Stratum basale of the epidermis.
Accessory Organs of the Skin
- Hair
- Nails
- Sebaceous glands (oil glands)
Hair Development
Individual hairs develop in the hair follicle.
Hair Growth: As new cells form at the base of the follicle, older cells are pushed out, forming the hair shaft.
Arrector Pili
A bundle of smooth muscle attached to the hair follicle.
Effect: Goosebumps. In response to cold, fear, or strong emotion, the arrector pili contracts, causing the hair shaft to stand up.
Sebaceous Glands
Oil glands.
Importance of Oil Secretion: Helps moisturize and waterproof skin and hair, and inhibits bacteria.
Sudoriferous Glands
Sweat glands.
Types:
- Eccrine: Active throughout life, respond to increased body temperature.
- Apocrine: Become active at puberty, respond to temperature and emotional stress, most numerous in axillary and genital regions.
Body Temperature Regulation
- If you get too hot:
- Dermal blood vessels dilate, allowing more blood (and heat) near the skin’s surface. Heat is lost through the skin.
- Sweat glands become active, and sweat evaporates from the skin.
- If you get too cold:
- Dermal blood vessels constrict, keeping blood away from the body surface.
- Skeletal muscles shiver, generating heat.
Brain Control of Body Temperature Set Point
The hypothalamus controls the set point for body temperature.