A&P POWER POINT NOTES
Introduction to Human Anatomy and Physiology
1.1 Introduction: History of the Study of the Human Body
Early students of anatomy and physiology primarily focused on treating illnesses and injuries.
Initial healing practices were based on:
Superstitions and magic.
Use of herbs and natural chemicals for treating ailments.
Methodology of studying anatomy involved:
Dissection of cadavers to learn about the human body.
Development of techniques for accurate observation and experimentation.
The language of anatomy and physiology is rooted in Greek and Latin terminology.
The scientific method was used to gather information about the body’s functions and interactions.
1.2 Anatomy and Physiology
Definition of Terms:
Anatomy: The study of the structure (morphology) of the body and its parts, focusing on form and organization.
Physiology: The study of the functions of these parts and their interactions.
Interrelationship of Anatomy and Physiology:
The functional role of a body part is intrinsically linked to its structure.
Methodologies Employed:
Anatomists utilize observation and dissection.
Physiologists depend on experimentation.
New discoveries are more frequently made in physiology, although anatomical discoveries continue to occur.
1.3 Levels of Organization
1.3.1 Composition of Materials
All materials, both non-living and living, are made up of chemicals.
1.3.2 Hierarchical Structure of the Body
Levels of Organization:
Atoms: The smallest unit of a chemical.
Molecules: Comprised of two or more atoms.
Macromolecules: Larger particles made from smaller molecules bound together.
Cells: The smallest unit to display the characteristics of life, with the human body consisting of approximately 37 trillion cells.
Tissues: Groups of cells working together.
Organs: Groups of tissues that perform specialized functions.
Organ Systems: Groups of organs functioning together.
Organisms: Composed of multiple organ systems functioning in unison.
1.3.3 Visual Representation
Figure 1.3: Levels of Organization
Levels illustrated include Atom, Molecule, Macromolecule, Cell, Tissue, Organ, Organ System, Organism.
1.4 Characteristics of Life
1.4.1 Shared Traits
All organisms exhibit certain characteristics:
Growth: Increase in body size, and cell size and number.
Reproduction: The creation of new organisms or cells.
Responsiveness: Reaction to environmental changes.
Movement: Change in position of the body or internal organs.
1.4.2 Metabolism
Metabolism (nutrient cycling): Combination of all chemical reactions within cells, encompassing:
Respiration: Energy release from food using oxygen, resulting in carbon dioxide release.
Digestion: Breakdown of food into usable forms for absorption into the bloodstream.
Circulation: Movement of cells and chemicals via body fluids.
Excretion: Removal of metabolic wastes.
1.5 Maintenance of Life
1.5.1 Environmental Factors
Requirements for sustaining life include:
Water: The most abundant chemical in the body, vital for metabolic processes, temperature regulation, and as a transport medium.
Oxygen and Carbon Dioxide: Essential for energy release and as a waste product of metabolism.
Food (Nutrients): Supplies energy necessary for bodily processes.
Wastes: Must be excreted from the body to maintain health.
1.5.2 Additional Life Requirements
Heat:
A form of energy crucial for the control of reaction rates in the body.
Pressure:
Atmospheric pressure is vital for breathing; hydrostatic pressure helps circulate blood.
1.6 Homeostasis
1.6.1 Concept of Homeostasis
Maintenance of a stable internal environment amidst changes in the external environment, regulated through homeostatic mechanisms.
Components of Homeostatic Mechanisms:
Receptors: Detect changes in the internal environment.
Set Point: The normal value for a variable.
Effectors: Glands or muscles responding to return conditions to stability.
1.6.2 Regulation and Control Systems
The body regulates various factors (temperature, pressure) within a specific range.
Examples of Homeostatic Mechanisms:
Body Temperature Regulation: Functions similarly to a thermostat; receptor detects temperature changes, effectors bring temperature back to set point.
Blood Pressure Regulation: Involves pressure-sensitive receptors and muscle actions in blood vessels.
1.6.3 Negative Feedback
A mechanism correcting deviations in a variable from its set point.
When receptors detect deviation, effectors return conditions to normal.
As the variable returns to the set point, the effectors’ activity lessens to prevent overshooting.
Example: Thermostat systems in homes.
1.6.4 Temperature Regulation Examples
1.6.4.1 Cold Environmental Responses
Detection: Thermoreceptors identify a drop in body temperature.
Response: Blood vessels in the skin constrict, and shivering generates heat.
1.6.4.2 Warm Environmental Responses
Detection: Thermoreceptors identify a rise in body temperature.
Response: Activation of sweat glands, increased blood flow to skin, and elevation of breathing rate to expel heat.
1.7 Contributions by Organ Systems to Homeostasis
Various organ systems maintain homeostasis in different ways:
Digestive System: Brings nutrients into the body.
Respiratory System: Supplies oxygen and eliminates carbon dioxide.
Cardiovascular System: Distributes nutrients and removes wastes.
Urinary System: Removes metabolic wastes and maintains water and electrolyte balance.
1.8 Positive Feedback Mechanisms
These systems amplify deviations from set points but are less common due to potential instability.
Short-lived mechanisms eventually lead to homeostasis, for example:
Blood clotting intensifies until a fracture in a vessel is sealed.
Uterine contractions during childbirth facilitate further contractions leading to delivery.
1.9 Organization of the Human Body; Body Cavities
1.9.1 Axial and Appendicular Portions
The body can be classified into:
Axial Portion: Head, neck, trunk.
Appendicular Portion: Upper and lower limbs.
1.9.2 Body Cavities
Cavities that house organs include:
Cranial Cavity: Houses the brain.
Vertebral Canal: Houses the spinal cord.
Thoracic Cavity: Contains the heart, lungs, and mediastinum.
Abdominopelvic Cavity: Divided into the abdominal cavity (contains stomach, liver, among others) and pelvic cavity (contains bladder and reproductive organs).
Diaphragm: A muscle dividing the thoracic and abdominopelvic cavities.
1.9.3 Small Cavities in the Head
Various small cavities include:
Oral Cavity: Contains mouth area, tongue, and teeth.
Nasal Cavity: Divided by the nasal septum and contains sinuses.
Orbital Cavities: Contain the eyes with associated muscles and nerves.
Middle Ear Cavities: Contain middle ear bones.
1.9.4 Membranes Surrounding Cavities
Thoracic and Abdominopelvic Membranes:
Double-layered membranes (parietal and visceral) surround organs; include pleural, pericardial, and peritoneal membranes.
Serous Fluid: Separates membrane layers, facilitating organ movement.
1.10 Organ Systems
1.10.1 Overview
The human body is composed of several organ systems, each functioning collaboratively to preserve homeostasis.
1.10.2 Integumentary System
Provides protective covering, regulation of body temperature, sensory reception, and synthesis of certain products.
1.10.3 Support and Movement Systems
Skeletal System: Composed of bones, ligaments, and cartilages that support and protect soft tissues, and produce blood cells.
Muscular System: Includes muscles that provide movement and posture, generating heat.
1.10.4 Integration and Coordination Systems
Nervous System: Composed of the brain, spinal cord, and nerves, facilitates communication using neurotransmitters.
Endocrine System: Consists of glands secreting hormones, slower response than nervous system but longer lasting effects.
1.10.5 Transport Systems
Cardiovascular System: Distributes oxygen, nutrients, and hormones while removing wastes.
Lymphatic System: Drains excess tissue fluid, returning it to the bloodstream; plays a role in immune defense.
1.10.6 Absorption and Excretion Systems
Digestive System: Processes food and absorbs nutrients; eliminates waste.
Respiratory System: Facilitates gas exchange (O2 and CO2) through the lungs.
Urinary System: Maintains water and electrolyte balance; excretes wastes.
1.10.7 Reproductive Systems
The reproductive systems produce new organisms; includes male and female reproductive organs with specific functions for gamete production and offspring development.
1.11 Anatomical Terminology
1.11.1 Anatomical Position Definition
The body is upright, facing forward, with upper limbs at sides and palms facing forward.
1.11.2 Terms of Relative Position
Superior: Above another part.
Inferior: Below another part.
Anterior (Ventral): Toward the front.
Posterior (Dorsal): Toward the back.
Medial: Closer to the midline.
Lateral: Away from the midline.
Bilateral: Paired structures on either side.
Ipsilateral: Structures on the same side.
Contralateral: Structures on opposite sides.
Proximal: Closer to the point of attachment.
Distal: Further from the point of attachment.
Superficial/Peripheral: Near the surface.
Deep: More internal than other structures.
1.11.3 Terminology of Body Sections
Sagittal Section: Divides body into right and left portions; midsagittal is equal parts, parasagittal is unequal.
Transverse Section: Divides body into superior and inferior portions.
Frontal (Coronal) Section: Divides body into anterior and posterior portions.
1.11.4 Sections in Cylindrical Organs
Cross Section: Cut across the structure.
Oblique Section: Angular cut through the structure.
Longitudinal Section: Lengthwise cut through the structure.
1.11.5 Body Region Terminology
Otic: Ear.
Nasal: Nose.
Oral: Mouth.
Cervical: Neck.
Acromial: Point of shoulder.
Axillary: Armpit.
Mammary: Breast.
Brachial: Arm.
Antecubital: Front of elbow.
Abdominal: Abdomen.
Antebrachial: Forearm.
Cephalic: Head.
Frontal: Forehead.
Orbital: Eye cavity.
Buccal: Cheek.
Mental: Chin.
Occipital: Back of head.
Sternal: Sternum.
Pectoral: Chest.
Umbilical: Navel.
Inguinal: Groin.
Coxal: Hip.
Lumbar: Lower back.
Sacral: Between hips.
Gluteal: Buttocks.
Carpal: Wrist.
Palmar: Palm.
Digital: Fingers.
Genital: External reproductive organs.
Patellar: Front of knee.
Crural: Leg.
Femoral: Thigh.
Popliteal: Back of knee.
Tarsal: Ankle.
Pedal: Foot.
Sural: Calf.
Calcaneal: Heel.
Plantar: Sole.