Human Anatomy and Physiology

Human Anatomy and Physiology

Introduction

• Medical Sciences form the foundation of healthcare, dealing with the study of human structure, function, health, and disease.
• They include multiple disciplines:
• Anatomy – study of the structure of the human body and its parts.
• Physiology – study of how body parts function individually and collectively.
• Biochemistry – chemical processes in the body.
• Pathology – study of diseases and structural/functional changes.
• Pharmacology – study of drugs and their effects.
• Microbiology – study of microorganisms and their impact on health.
• Community Medicine – prevention and promotion of health at population level.
• Together, these sciences help healthcare professionals understand normal and abnormal functioning for diagnosis, treatment, and prevention of diseases.

Structural Organization of the Human Body

1 Basic Components

• Cells – smallest unit of life.
• Tissues – group of cells with similar function.
• Organs – structures made of different tissues working together.
• Organ Systems – organs working collectively for a major function.
• Organism – complete living human body.

2 Life Processes (Basic characteristics of life)

1. Metabolism – all chemical reactions (catabolism + anabolism).
2. Responsiveness – ability to detect/respond to changes.
3. Movement – motion of body/fluids/subcellular structures.
4. Growth – increase in size (cell number, size, or material).
5. Differentiation – unspecialized cells become specialized.
6. Reproduction – formation of new cells for growth/repair or a new individual.

3 Survival Needs

• Nutrients (carbohydrates, proteins, fats, vitamins, minerals).
• Oxygen (essential for energy production).
• Water (solvent, medium for reactions, transport, temperature regulation).
• Normal Body Temperature (37°C – necessary for enzyme function).
• Atmospheric Pressure (required for breathing and gas exchange).

4 Homeostasis

• Defined as the maintenance of a stable internal environment despite external changes.
• Controlled by feedback systems:
• Negative feedback – reverses a change (e.g., temperature regulation, blood glucose control).
• Positive feedback – enhances a change (e.g., labor contractions, blood clotting).

5 Levels of Structural Organization

1. Chemical level – atoms and molecules (DNA, proteins, water).
2. Cellular level – cells as structural and functional units.
3. Tissue level – epithelial, connective, muscular, nervous tissues.
4. Organ level – heart, lungs, liver, kidneys, etc.
5. System level – cardiovascular, digestive, nervous systems.
6. Organismal level – complete living human body.

Cell Structure, Tissues, and Organ Systems Overview

1 Cell Structure

• Plasma Membrane – regulates entry/exit of substances.
• Cytoplasm – fluid with organelles.
• Nucleus – control center with DNA.
• Organelles:
• Mitochondria (energy production).
• Endoplasmic Reticulum (protein & lipid synthesis).
• Ribosomes (protein synthesis).
• Golgi Apparatus (packaging & secretion).
• Lysosomes (digestion).
• Centrioles (cell division).

2 Tissues (Four Basic Types)

1. Epithelial tissue – covers surfaces, lines cavities, forms glands.
2. Connective tissue – supports, protects, binds (bone, cartilage, fat, blood).
3. Muscle tissue – movement (skeletal, cardiac, smooth).
4. Nervous tissue – transmits impulses, coordinates activities.

3 Overview of Organ Systems

1. Integumentary – skin, hair, nails (protection, regulation).
2. Skeletal – bones, joints (support, movement, blood formation).
3. Muscular – skeletal muscles (movement, heat production).
4. Nervous – brain, spinal cord, nerves (control, coordination).
5. Endocrine – glands (hormone regulation).
6. Cardiovascular – heart, blood, vessels (transport, defense).
7. Lymphatic/Immune – lymph nodes, spleen (immunity, fluid balance).
8. Respiratory – lungs, airways (gas exchange).
9. Digestive – GI tract, accessory organs (nutrition, absorption).
10. Urinary – kidneys, bladder (waste removal, fluid balance).
11. Reproductive – testes, ovaries, related structures (reproduction).

Basic Terminology in Anatomy and Physiology

1 Cells

• Smallest structural and functional unit of life.

2 Glands

• Exocrine glands – secrete into ducts (sweat, salivary).
• Endocrine glands – secrete hormones into blood (thyroid, pituitary).

3 Body Fluids

• Intracellular fluid (ICF) – inside cells (~2/3 of body fluid).
• Extracellular fluid (ECF) – outside cells (~1/3):
• Interstitial fluid (between cells).
• Plasma (blood fluid).
• Other fluids (CSF, synovial, lymph).

4 Membranes

• Mucous membranes – line cavities open to exterior (respiratory, GI).
• Serous membranes – line closed cavities (pleura, pericardium, peritoneum).
• Synovial membranes – line joint cavities.
• Cutaneous membrane – skin.

5 Anatomical Positions

• Standard Anatomical Position – standing erect, face forward, arms at side, palms facing forward.

6 Body Cavities

• Dorsal cavity – cranial, vertebral.
• Ventral cavity – thoracic (pleural, pericardial, mediastinum), abdominal, pelvic.

7 Planes and Sections

• Sagittal plane – divides left & right.
• Midsagittal – equal halves.
• Parasagittal – unequal halves.
• Frontal (coronal) – divides front & back.
• Transverse (horizontal) – divides top & bottom.
• Oblique – diagonal cuts.

8 Abdominal Quadrants and Regions

• Quadrants: Right Upper (RUQ), Left Upper (LUQ), Right Lower (RLQ), Left Lower (LLQ).
• Nine Regions: hypochondriac (R & L), epigastric, lumbar (R & L), umbilical, iliac/inguinal (R & L), hypogastric.

9 Directional Terms

• Superior / Inferior – above / below.
• Anterior (ventral) / Posterior (dorsal) – front / back.
• Medial / Lateral – toward / away from midline.
• Proximal / Distal – nearer / farther from point of origin.
• Superficial / Deep – near surface / away from surface.

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