Anatomy and Physiology: History and Organization

• Early healers used superstition and magic, later evolving to make observations of injuries and wounds.
• Experimentation led to the creation of new terminology for anatomy and physiology.
• The study of corpses and cadaver dissection led to knowledge of the human body.

Anatomy & Physiology

• Anatomy is the study of the structure/morphology of the human body and its parts, derived from the Greek term for "a cutting up."
• Physiology is the study of the functions of the human body and its parts, derived from the Greek term for "relationship to nature."
• The structure of organs and parts in the human body determines their function.

Levels of Organization

• All materials, living or non-living, consist of atoms.
• Subatomic Particles, such as protons, neutrons and electrons, make up cells.
• Atoms are tiny particles that make up chemicals like hydrogen and carbon.
• Molecules consist of atoms joined together, exemplified by water and glucose.
• Macromolecules are large particles formed by molecules, like DNA and protein.
• Organelles are functional parts of a cell, such as mitochondria and lysosomes.
• A Cell is the basic unit of structure and function, categorized as muscle, nerve, or blood cells.
• Tissue is a layer or mass of cells performing a specific function, e.g., adipose tissue.
• An Organ: is a group of different tissues with a function, exemplified by the heart, kidney, and stomach.
• An Organ System is a group of organs with a common function, such as the digestive system.
• An Organism is composed of interacting organ systems, e.g., a human.

Clinical Applications

• Ultrasound uses high-frequency sound waves to image soft internal structures, used to obtain sonograms of a fetus.
• Magnetic Resonance Scan (MR) uses a magnetic field to change the alignment and spin of atoms, providing high-resolution images of internal structures like the brain.

Core Themes of Anatomy & Physiology

• The cell is the basic unit and all living things consist of cells.
• The Internal Environment: is the environment within body.
• Homeostasis is the maintenance of a constant internal environment.
• Interdependency of Cells: Cells depend on each other.
• Structure and function in the body are interrelated.
• Gradients and permeability: Cells move from high to low, down pressure and concentration gradients, across permeable membranes.
• Cellular differentiation: Specialization of cells due to gene expression.
• Cell membrane mechanisms: Determine transport of substances, and responds to signals.
• Cell-to-cell communication occurs via membrane receptors.
• Feedback loops: Homeostatic mechanisms create stability.
• Balance: Replacement of lost substances, and elimination of excesses
• Energy processes: Keeps cells active.

Characteristics of Life

• Growth: Increase in cell number and size and increase in body size.
• Reproduction: Production of new cells and organisms.
• Responsiveness: Reaction to a change inside or outside of the body.
• Movement: Change in body position or location; motion of internal organs.
• Metabolism is the sum of all chemical reactions in a living system, including energy production and nutrient cycling.
• Respiration, energy is created by taking in oxygen and giving off carbon dioxide.
• Digestion is the breaking down food into usable nutrients for absorption into the blood.
• Circulation involves moving chemicals and cells through the body fluids.
• Excretion involves removing waste products.

Requirements of Organisms

• Life requires environmental factors: Water, food, oxygen, heat, and pressure.
• Chemicals: is a substance with a specific molecular composition that is produced by or used in a reaction involving changes to atoms or molecules.
• Water: is the most abundant substance in body.
• Water: provides the environment for metabolic processes (intracellular and extracellular fluids).
• Water: is also Required for transport of substances, and, regulation of body temperature.
• Food provides necessary nutrients to supply energy.
• Oxygen releases energy from food.
• Heat is a form of energy, maintains body temperature, and partly controls the rate of metabolic reactions.
• Pressure: is the Application of force on an object.
• Atmospheric pressure : is important for breathing.
• Hydrostatic pressure keeps blood flowing.

Homeostatic Mechanisms

• Homeostatic Mechanisms: Self-regulating systems monitor aspects of the internal environment and correct them as needed.
• Receptor: detects and provides information about the stimuli.
• Control Center: maintains the set point.
• Effector: muscle or gland that responds to the control center, an causes the necessary change in the internal environment.

Feedback

• Negative Feedback: Most common type of homeostatic mechanism.
• With Negative Feedback, effectors return conditions toward normal range, and the deviation from set point lessens
• With Negative Feedback, the response to the change moves the variable in the opposite direction of the deviation from the set point.
• Negative Feedback prevents sudden, severe changes in the body.
• Examples of Negative Feedback: Controls body temperature, blood pressure, and glucose level in the blood.
• Positive Feedback:. Uncommon feedback mechanism where the change/deviation is intensified, instead of reversed.
• With Positive Feedback, the activity of the effector is increased initially, instead of decreasing.
• Positive Feedback is short-lived.
• Positive Feedback creates unstable conditions, that seem like they will not lead to homeostasis, but they will.
• Examples of Positive Feedback: Blood clotting and the uterine contractions of childbirth.

Organization of the Human Body

• The Axial portion includes the head, neck, and trunk.
• The Appendicular portion includes the: upper and lower limbs.
• Major body cavities of the axial portion:
• Cranial cavity houses the brain.
• Vertebral canal (spinal cavity) contains the spinal cord.
• Thoracic cavity houses the lungs and thoracic viscera.
• Abdominopelvic cavity contains the abdominal and pelvic viscera.
• Diaphragm is a muscle that separates the thoracic and abdominopelvic cavities.
• Mediastinum: is the region between lungs in thoracic cavity, which contains heart, esophagus, trachea, and thymus gland.
• Abdominopelvic cavity contains 2 portions: the Abdominal and Pelvic Cavities.
• Abdominal cavity: extends from diaphragm to top of pelvis, and contains stomach, liver, spleen, kidneys small intestine, most of large intestine.
• Pelvic cavity: is enclosed by pelvic bones, and contains end of large intestine, urinary bladder, internal reproductive organs.

Cavities of the Head

• Cavities of the head include the Oral, Nasal, Orbital, and Middle ear Cavities.

Serous Membranes

• Thoracic and abdominopelvic cavities: The cavities are lined by double-layered serous membranes, which secrete serous fluid which prevents friction between layers.
• The Serous membrane is consist of two layers:
• Visceral layer: inner layer, which covers an organ.
• Parietal layer: outer layer, which lines the wall of cavity.
• Examples of serous membranes: are the: Visceral and parietal pleura (around lungs in thorax), Visceral and parietal pericardium (around heart in thorax) and Visceral and parietal peritoneum (around abdominopelvic organs).

Organ Systems

• Integumentary System: provides body covering, protection, aids in body temperature regulation, sensory reception, and production of Vitamin D
• Skeletal System: supports and provides movement, framework, protection, and attachment sites; it also stores inorganic salts, and produces, blood cells
• Muscular System: provides support and movement and is the main source of body heat, that maintains posture.
• Nervous System: integrates and coordinates of organ function through nerve impulses and neurotransmitters; produces rapid short-term effects
• Endocrine system: integrates and coordinates organ functions through chemical messengers called hormones and elicits slower, longer lasting effects.
• Cardiovascular System: transports gases, nutrients, blood cells, hormones, and wastes throughout the body.
• Lymphatic System: transports fluids from tissue spaces to blood and carries fats from the digestive system to blood to defend the body against infection
• Digestive System: receives, breaks down food, absorbs digestive products, and excretes waste.
• Respiratory System: introduces and removes air in and out of the body and exchanges gases (oxygen and carbon dioxide) between blood and air and absorbs oxygen.
• Urinary System: removes blood wastes, regulates electrolyte & water balance and blood pressure, produces urine and excretes it by transporting it to outside of body.
• Reproductive System: Male and female systems produce and transport sex cells, produce hormones, and produce new like organisms; the female also provides for fetal development and childbirth.

Aging

• Aging occurs from the microscopic to the whole-body level.
• Hair loses pigment and becomes gray or white.
• The skin wrinkles due to a decrease in subcutaneous fat, and the body stiffens due to decrease in collagen and elastin.
• The body encounters a percentage of fats in the tissues increases.
• Joints develop stiffness.
• Elevated blood pressure may progress to hypertension.
• Elevated blood glucose may progress to type 2 diabetes mellitus.
• Tissues atrophy and organs shrink.
• Cells reach end of ability to undergo cell division, as they lose tips of chromosomes.
• Metabolic rate decreases.
• Decreased production of enzymes and other proteins.
• Dementia/Alzheimer disease.

Anatomical Terminology

• Anatomical Position is Standing erect, facing forward, with upper limbs at the sides, and palms facing forward.
• Anatomical terms of relative position are based on a person standing in anatomical position.
• Superior (above) is also Inferior (below).
• Anterior or ventral (toward the front) is also Posterior or dorsal (toward the back).
• Medial (toward the midline) is also Lateral (away from midline).
• Bilateral includes paired structures; on both sides.
• Ipsilateral (same side) and Contralateral (opposite sides).
• Proximal (close to point of attachment to trunk) and Distal (farther from point of attachment to trunk).
• Superficial (close to body surface) and Deep (more internal). There are several Body Sections or Planes.
• Sagittal section : is a longitudinal cut that divides body into left and right portions
• Mid-sagittal/Median section : and divides body into equal left and right portions
• Parasagittal section : which is a sagittal section lateral to midline, that divides body into unequal left and right portions.
• Transverse or Horizontal section : divides body into superior and inferior portions
• Coronal or Frontal section : is a longitudinal cut that divides body into anterior and posterior portions.
• Cross section: A cut across the structure.
• Oblique section: An angular cut.
• Longitudinal section: A lengthwise cut.