Introduction to Anatomy and Physiology

Anatomy

• Anatomy involves studying the body's structure and shape, along with its various components.
• Observation helps determine the sizes of body parts and their interrelationships.

Gross Anatomy

• Gross anatomy deals with large, easily observable structures.

Microscopic Anatomy

• Microscopic anatomy focuses on structures too small for the naked eye.
• Microscopes are needed to view cells and tissues.

Physiology

• Physiology examines how the body and its parts function.
• Structure determines function

Levels of Structural Organization

• Six levels of structural organization: atoms, cells, tissues, organs, organ systems, and organisms.

Chemical Level

• Atoms unite to create molecules

Cellular Level

• Cells are composed of molecules

Tissue Level

• Tissues consist of similar types of cells

Organ level

• Organs comprises different types of tissues

Organ System Level

• Organ systems comprises different organs that work closely together.

Organismal Level

• Human organisms are made up of many organ systems.

Organ System Overview

Integumentary System

• Forms the body's external covering i.e. skin, including hair and fingernails.
• Waterproofs the body.
• Cushions and protects deeper tissues from injury.
• Synthesizes vitamin D with the help of sunlight.
• Excretes salts through perspiration.
• Regulates body temperature.
• Cutaneous nerve receptors are located here.

Skeletal System

• Comprises bones, cartilages, ligaments, and joints.
• Facilitates muscle attachment for movement.
• Protects vital organs.
• Is the location of blood cell formation.
• Stores minerals.

Muscular System

• Skeletal muscles contract, resulting in movement of bones.

Nervous System

• It acts as a fast-acting control system.
• Encompasses the brain, spinal cord, nerves, and sensory receptors.
• Responds to internal and external stimuli.
• Sensory receptors are responsible for detecting changes .
• Messages are relayed to the central nervous system, which then assesses the information and activates effectors, such as muscles and glands.

Endocrine System

• Secretes hormones into the bloodstream.
• Regulates body functions: growth, reproduction, and nutrient utilization.
• Endocrine glands: pituitary, thyroid, parathyroid, adrenal, thymus, pancreas, pineal, ovaries (females), and testes (males).

Cardiovascular System

• Includes the heart and blood vessels.
• The heart's function is to pump blood.
• Vessels transport blood to tissues.
• Blood transports oxygen, carbon dioxide, nutrients, and hormones.
• Blood contains white blood cells for protection from foreign substances.

Lymphatic System

• Comprises lymphatic vessels, lymph nodes, and lymphoid organs.
• Complements the cardiovascular system by returning leaked fluids to the bloodstream.
• Lymph nodes cleanse the blood.
• Houses white blood cells function in immunity.

Respiratory System

• Includes the nasal passages, pharynx, larynx, trachea, bronchi, and lungs.
• Allows gas exchange with the blood in the air sacs found inside the lungs.
• Supplies oxygen to the body.
• Removes carbon dioxide.

Digestive System

• Includes the oral cavity (mouth), esophagus, stomach, small and large intestines, rectum, and accessory organs.
• Breaks down food.
• Enables nutrient absorption into the blood.
• Eliminates undigested material as waste.

Urinary System

• Includes the kidneys, ureters, urinary bladder, and urethra.
• Eliminates nitrogenous wastes.
• Maintains acid-base balance.
• Regulates water and electrolyte balance.
• Regulates normal blood pressure.

Reproductive System

• Male: testes, scrotum, penis, accessory glands, and duct system, testes produce sperm, and the duct system carries sperm.
• Female: ovaries, uterine tubes, uterus, and vagina, ovaries produce eggs, and the uterus provides a site for fetal development.

Necessary Life Functions

• Maintains boundaries that separate the "inside" from the "outside."
• Movement: includes locomotion and the movement of substances.
• Responsiveness (irritability): involves sensing change and reacting.
• Digestion: Breakdown and absorption of nutrients.
• Metabolism: chemical reactions within the body
• Excretion: Removal of excreta (waste) from metabolic reactions, possibly in urine, feces, or sweat.
• Reproduction: occurs on the cellular level or organismal level, used for growth and repair.
• Growth: Increases cell size/body size by increasing the number of cells, regulated by hormones.

Survival Needs

• Nutrients: Chemicals for energy and cell building including carbohydrates, proteins, lipids, vitamins, and minerals
• Oxygen: Needed for chemical reactions, by respiratory and cardiovascular systems
• Water: Comprises 60-80% of body weight, the most abundant chemical in the human body, offers a fluid base for body secretions and excretions.
• Normal body temperature: 37°C (98.6°F), affecting chemical reactions.
• Atmospheric pressure: needed for gas exchange

The Language of Anatomy

• Special terminology is used to prevent confusion.
• Precise terms are used for position, direction, regions, and structures.
• Anatomical position: Standing erect, feet parallel, arms hanging at the sides with palms facing forward, and away from the body.

Directional Terms

• Directional terms explain the location of one body structure in relation to another.
• Superior (cranial or cephalic): toward the head or upper part of the body.
• Inferior (caudal): Away from the head or toward the lower part of the body.
• Anterior (ventral): toward or at the front of the body
• Posterior (dorsal): Toward or at the backside of the body.
• Medial: toward or at the midline of the body.
• Lateral: away from the midline of the body.
• Intermediate: between a medial and lateral structure.
• Proximal: close to the origin of the body part.
• Distal: farther away from the origin of the body part.
• Superficial (external): toward or at the body surface.
• Deep (internal): Away from the body surface.
• Know the Regional Terms - Anterior and posterior body landmarks

Body Planes and Sections

• Sections – cuts along imaginary lines known as planes
• Sagittal: divides the body into left and right parts.
• Frontal (coronal): divides the body into anterior and posterior.
• Transverse (cross): divides the body into superior and inferior parts.

Body Cavities

• Two internal body cavities-Dorsal and Ventral
• Cavities offer protection to the organs within.
• Dorsal body cavity’s subdivisions-Cranial and Spinal cavity
• Ventral body cavity has two subdivisions divided by the diaphragm-Thoracic and Abdominopelvic
• Thoracic cavity: Superior to the diaphragm, houses heart, lungs, and other organs, mediastinum in the central region and protected by the rib cage
• Abdominopelvic cavity: Inferior to diaphragm, containing the stomach, liver, reproductive organs, bladder, and rectum
• Abdominopelvic cavity can be broken down into four quadrants and nine regions.
• Other body cavities exist including digestive, nasal, orbital and middle ear.

Homeostasis

• It is a maintenance of relatively stable internal conditions .
• It is a balance needed for sustaining life.
• The nervous and endocrine systems are the main controlling systems.
• An imbalance in this results in disease.

Maintaining Homeostasis

• Control mechanisms need a receptor, control center, and effector.
• Receptor has responses to environmental changes.
• Information is sent to the control center by way of an afferent pathway.
• The control center has a set point, which analyzes information and determines the correct response.
• Effector gives the means of response to stimulus
• Information comes from the control center to effector by way of an efferent pathway.

Feedback Mechanism

• Negative feedback: controls homeostatic mechanisms by reducing the intensity.
• Positive feedback: Increases the stimulus and occurs during blood clotting and the birth of a baby.