Human Cells and Body Structures: Module 1
Introduction to Human Cells
Instructor: Rainey Tronsell
Course: ANP209 (Human Anatomy & Physiology)
Focus: Human cells and body structure
Goal: Identify parts of a typical cell and name each part's functions
Overview of Cells
Body Composition:
The human body consists of trillions of cells with identical genetic makeup.
Cell Identity:
Despite having identical genes, cells are not identical blobs.
Gene expression varies, leading to different cell types.
Common Cell Types:
Epithelial cells
Blood cells
Bone cells
Muscle cells
Nerve cells
Cell Behavior:
Some cells (e.g., blood cells) are unattached and act independently.
Other cells form tissues by attaching to each other and performing collective functions.
Cellular Dynamics
Cell Replacement:
Most cells are constantly replaced, except for certain types, like nerve cells.
Damage to nerve cells results in loss of function.
Epithelial Cells in the Respiratory Tract
Reference to epithelial cells with cilia found in the respiratory tract.
Links to additional resources under Unit One Learning Activities.
Structure and Function of a Typical Cell
Cell Membrane (Plasma Membrane):
Separates the cell's internal environment from the external environment.
Contents: Intracellular fluid and organelles.
Composition: Double layer of phospholipids.
Functionality:
Selectively permeable: Allows certain substances (e.g. ions, nutrients, waste products) to pass.
Transport Mechanisms:
Passive Transport: Movement without energy input (using kinetic energy).
Types:
Simple Diffusion:
Movement from high to low concentration without energy.
Examples: Oxygen enters cells, Carbon dioxide exits cells.
Influencing Factors:
Concentration gradient steepness
Temperature (higher temperature increases diffusion)
Mass of substance
Surface area
Distance for diffusion
Osmosis:
Movement of water through a selectively permeable membrane.
Definition: Movement from high concentration of water/low concentration of solutes to low concentration of water/high concentration of solutes.
Mechanisms:
Through phospholipid bilayer or aquaporins (specialized water channels).
Filtration:
Movement due to pressure differences rather than concentration differences.
Active Transport Mechanisms
Definition: Active transport uses cellular energy (ATP) to move substances against their concentration gradient.
Types of Active Transport:
Sodium-Potassium Pump (main example of active transport):
Pumps sodium ions out (3 per ATP) and potassium ions in (2 per ATP) against their concentrations.
Endocytosis:
Process of taking substances into the cell by engulfing them in a vesicle.
Types:
Phagocytosis: Engulfing large particles (e.g., pathogens).
Receptor-mediated endocytosis: Specific molecules are engulfed.
Pinocytosis: Engulfing liquids.
Exocytosis:
Process of releasing substances from the cell by fusing vesicles with the plasma membrane.
Vesicle Definition: A small spherical sac formed from a membrane.
Cytoplasm and Its Components
Cytoplasm: All contents inside the cell except the nucleus. Consists of organelles and cytosol (the fluid).
Endoplasmic Reticulum (ER):
A network of membrane-enclosed tubules and sacs (cisterna).
Types:
Rough ER: Studded with ribosomes, responsible for protein synthesis.
Smooth ER: Lacks ribosomes, involved in lipid metabolism and various regulatory functions.
Golgi Apparatus: Receives proteins from the rough ER, packages them into vesicles, and ships them to their final destinations. Synthesizes glycolipids and sphingomyelin.
Lysosomes: Contain enzymes that digest unneeded cellular components and destroy pathogens (autophagy).
Mitochondria: "Powerhouse of the cell" that produces ATP from nutrient molecules (e.g., glucose).
Contain their own DNA, inherited from the mother, can replicate during increased demand.
Peroxisomes: Contain enzymes for lipid metabolism and detoxification. Convert hydrogen into hydrogen peroxide to neutralize poisons.
Cytoskeleton: A dynamic network of protein filaments that organizes cell contents, connects cells to their environment, and generates movement.
Nucleus
Definition: Central organelle of the cell.
Functions:
Stores hereditary material (DNA).
Coordinates cellular activities (protein synthesis, cell division, and growth).
Some cells may have multiple nuclei while others lack a nucleus altogether.
Additional Resources
Recommended reading on DNA replication and cell growth/division.
Suggested layout for mind maps and component identification.
Questions to test knowledge on cell membrane functions to be discussed in a live session.
Conclusion
Objective assessment on understanding of unit concepts should be completed.
Encourage reviewing materials for comprehension and retention.
Introduction to Body Cavities and Membranes in ANPH 209
Objectives:
Identify major body cavities and their subdivisions.
Describe the major organs contained within each cavity.
Explain the membranes of the ventral body cavity.
Body Regions Overview:
Divided into:
Head and neck.
Three trunk regions: thorax, abdomen, pelvis.
Upper limb and lower limb.
Terminology Note: Avoid using "arms" and "legs"; use "upper limb" and "lower limb" instead.
Major Body Cavities
Definition of Cavities:
Spaces within the body that protect, separate, and support internal organs.
Each cavity is lined by a membrane and contains specific organs.
The Five Main Body Cavities:
Cranial cavity
Formed by cranial bones (skull bones).
Function: Protects the brain.
Contains:
Brain (cerebrum)
Protective coverings (meninges)
Cerebrospinal fluid (CSF)
Shock Absorption Function.
Vertebral Canal
Long, thin cavity surrounded by bones of the vertebral column.
Contains:
CSF and meninges (similar to cranial cavity).
Spinal cord and beginnings of spinal nerves.
Connection with Cranial Cavity:
Communicates at foramen magnum (base of the skull).
Thoracic Cavity
Superior subdivision of the anterior cavity, enclosed by the rib cage (includes ribs, sternum, thoracic vertebrae).
Contains multiple organs, prominently:
Two lungs.
Heart.
Subdivided into:
Two pleural cavities (for lungs).
Mediastinal cavity (between lungs).
Extends from the first rib to the diaphragm.
Mediastinum:
Further subdivided into:
Superior Mediastinum (orange):
Contains esophagus, trachea, thymus gland, large vessels exiting the heart.
Pericardial Cavity (turquoise):
Contains the heart.
Importance of Diaphragm:
Forms floor of thoracic cavity, separates it from the abdominal cavity.
Abdominal Cavity
Largest cavity in the body, extends from diaphragm to groin.
Enclosed by abdominal wall, related muscles, and bones.
Contains:
Digestive organs (e.g., stomach, small/large intestines, liver, gallbladder, spleen, kidneys).
Each specific organ is responsible for various digestive functions.
Pelvic Cavity
Continuation of the abdominal cavity, no membrane physically separating the two.
Contains:
Reproductive organs.
Urinary bladder.
Final portions of large intestine and urethra.
Membranes of the Ventral Body Cavity
Membrane type: Peritoneum lines the abdominopelvic cavity.
Functions:
Allows mobility of digestive organs for digestion and peristalsis.
Facilitates passage of neurovascular structures (arteries, veins, nerves) to/from organs.
Adipose tissue can also accumulate within the peritoneum.
Division of the Abdominopelvic Cavity
Abdominopelvic cavity divided into:
Four quadrants or nine regions for clinical assessment.
Four Quadrant Division:
Vertical line through the median plane (divides into right/left halves).
Transverse line through the umbilicus (divides into upper/lower halves).
Results in: Right upper, left upper, right lower, left lower quadrants.
Nine Region Division:
Vertical lines through midclavicular planes (midpoints of clavicles).
Horizontal lines:
1. Subcostal line (through last costal cartilage).
2. Intertubercular (transtubercular) line (through anterior superior iliac spines).
Named regions:
Right hypochondriac
Left hypochondriac
Epigastric
Right lumbar
Left lumbar
Umbilical
Right iliac
Left iliac
Hypogastric.
Regional Names Meaning:
"Hypo" means below; "gastric" refers to stomach.
"Epigastric" means at stomach, "hypogastric" means below stomach.
Membranes of the Body
Four types of membranes:
Cutaneous membranes
Serous membranes
Mucous membranes
Synovial membranes
Serous Membranes
Focus on serous membranes in thoracic and abdominopelvic regions:
Structure:
Two layers:
Parietal layer (outer)
Visceral layer (inner, adheres to organs).
Function:
A potential space filled with serous fluid minimizes friction between organs during movement (e.g., heart contraction, lung expansion).
Example: Pericardial Cavity
Pericardium surrounds the heart:
Contains:
Fibrous pericardium (tough outer layer)
Serous pericardium (inner layer with parietal and visceral components).
Pericardial cavity between layers allows for heart movement without friction.
Example: Pleurae
Pleurae line thoracic wall and adhere to lung surfaces:
Functions of pleurae:
Reduction of friction
Creation of pressure gradient
Compartmentalization of thoracic cavity.
Main components:
Visceral pleura (attached to lung)
Parietal pleura (attached to thoracic wall and diaphragm).
Pathological Conditions:
Potential for the pleural cavity to fill with air or fluid (e.g., chest wound) raises clinical significance.
Summary
Understanding body cavities and membranes is essential for mastering anatomy and physiology.
Use various resources and diagrams to visualize and reinforce learned concepts.
Unit One Overview
Anatomical Position:
Definition: The body is considered in the anatomical position when described.
Characteristics of the Anatomical Position:
Body standing upright.
Face and eyes facing anterior (forward).
Arms are straight and adjacent to the body.
Palms facing anterior with thumbs pointing outward.
Legs straight, not bent.
Feet shoulder-width apart and parallel, toes pointing anteriorly.
Importance:
Standardizes terms of reference for describing positions of organs and structures, even if the body is in a different position.
Common Body Positions:
Prone: Face down orientation.
Supine: Face up orientation.
Usage: Relevant in specific physical examinations or radiologic procedures.
Directional Terminology
Standard Terms:
Superior:
Meaning: Towards the head or upper part of the body.
Example: The heart is superior to the stomach.
Inferior:
Meaning: Away from the head or lower part of the body.
Example: The liver is inferior to the right lung.
Cranial:
Meaning: Specifically towards the head.
Caudal:
Meaning: Towards the tail region, more relevant for animals.
Anterior:
Meaning: At the front of the body or in front of another structure.
Example: The sternum is anterior to the heart.
Ventral:
Meaning: Closer to the stomach or abdominal region.
Dorsal:
Meaning: Towards the back region.
Posterior:
Meaning: Behind another structure, applicable to all body regions.
Example: The esophagus is posterior to the trachea.
Medial:
Meaning: Nearer to the midline of the body.
Example: The nose is medial to the ears.
Lateral:
Meaning: Farther away from the midline.
Example: The ears are lateral to the nose.
Proximal:
Meaning: Nearer to the attachment of a limb to the trunk.
Example: The humerus is proximal to the ulna.
Distal:
Meaning: Farther from the attachment of a limb to the trunk.
Example: The phalanges are distal to the carpals.
Anatomical Planes
Definition: A plane is an imaginary two-dimensional surface that divides the body.
Importance: Useful in describing joint movements and for diagnostic medical imaging.
Types of Anatomical Planes:
Sagittal Plane:
Definition: Divides the body into right and left halves.
Median or Midsagittal: When the plane is in the midline, exactly dividing the body into equal halves.
Parasagittal: When the plane shifts away from the midline, creating unequal halves.
Frontal (Coronal) Plane:
Definition: Divides the body into anterior (front) and posterior (back) sections.
Orientation: Perpendicular to both sagittal and transverse planes.
Transverse Plane:
Definition: Divides the body into superior (top) and inferior (bottom) parts.
Also referred to as a horizontal plane.
Oblique Plane:
Definition: A plane that cuts through the body at an angle, not aligned with any of the standard planes.
Sections and Medical Imaging
Definition: A section is a two-dimensional surface resulting from slicing a three-dimensional structure.
Importance: Understanding the plane of section is critical for interpreting medical images (virtual sections).
Examples of Sections:
Sagittal Section: Created by cutting along the sagittal plane.
Frontal Section: Established by cutting along the frontal plane.
Transverse Section: Made by cutting along the transverse plane.
Practice and Revision
Additional resources available under content, unit one, learning activities for extra practice in anatomical positions, directional terms, and body planes.
Encourage discussion and revision sessions for students needing further clarification on the material.
Course Structure and Approach
Course materials and prerequisites:
First study unit: Human cells and body structure
Importance of completing the reading list before viewing the video:
Video serves as a summary and revision; understanding the textbook is crucial
Desired outcomes from the study unit:
Explain the organization of the human body
Discuss body functions necessary for life
Describe anatomical positions, directional terms, and planes
Identify major body cavities, subdivisions, and contained organs
Describe membranes of the ventral body cavity
Identify parts of a typical cell and their functions
Anatomy and Physiology Overview
Definition of Anatomy and Physiology:
Anatomy: The physical structure of the body and its organs and tissues.
Physiology: How the body structures work together.
Importance of Anatomy and Physiology:
Fundamental to health professions
Enhances understanding of medical terms, nutrition, medications, and procedures
Aids in understanding diseases
Subdivisions of Anatomy
Major subdivisions:
Gross Anatomy:
Study of larger structures visible to the naked eye.
Also known as macroscopic anatomy.
Relevant fields: paramedics, dental assistants, fitness management.
Microscopic Anatomy:
Study of structures observable only under a microscope.
Includes cytology (study of cells) and histology (study of tissues).
Logos: Means study of; indicates terms related to this field.
Levels of Organization in the Human Body
Six levels of organization:
Chemical Level:
Atoms are the smallest unit of matter that form molecules.
Cellular Level:
Molecules combine to form cells.
Tissue Level:
Cells group to form tissues.
Organ Level:
Tissues combine to form organs.
Organ System Level:
Organs group together to form organ systems.
Organism Level:
Organ systems combine to form a living organism.
Explanation of terms:
Cytology: Study of cells.
Histology: Study of tissues.
Definition of organs:
Structures composed of two or more tissue types working together.
Example organs: heart, lungs, kidneys, liver, brain.
The skin: the largest organ with smaller organs within it (hair, nails, glands, nerves).
Definition of organ systems:
Groups of organs with a collective function.
There are 11 organ systems in the human body:
Integumentary system
Skeletal system
Muscular system
Nervous system
Endocrine system
Cardiovascular system
Respiratory system
Digestive system
Lymphatic system
Urinary system
Reproductive system (male and female)
Survival Needs and Life Processes
Six important life processes:
Metabolism:
Involves chemical changes of molecules taken from the environment.
Composed of:
Anabolism: Building up body tissues and energy stores.
Catabolism: Breaking down tissues to release energy.
Reproduction:
Ability to produce offspring to pass on genes.
Movement:
Movement from place to place or moving substances internally.
Growth:
Increase in size through chemical changes.
Differentiation:
Transformation of unspecialized cells into specialized cells.
Responsiveness:
Ability to sense and react to environmental changes.
Example of responsiveness: Reaction to a 'squealing brake' sound.
Homeostasis
Definition of homeostasis:
Derived from Greek terms meaning 'same' and 'steady'.
Dynamic process maintaining stable internal conditions.
Importance of homeostasis:
Continuous monitoring of internal conditions (e.g., temperature, blood pressure).
Set point: Physiological value around which normal ranges fluctuate.
Example set point for body temperature: approximately .
Interaction of systems to restore normal parameters if disrupted.
Feedback Systems:
Components: Sensors (receptors), control center (brain), effectors.
Feedback Systems:
Negative Feedback: Reverses deviations from set points (e.g., blood glucose regulation).
Positive Feedback: Enhances changes in the system (e.g., childbirth).
Examples of feedback systems:
Negative Feedback Example:
Blood glucose control: Insulin release when high glucose is detected.
Positive Feedback Example:
Childbirth; involves enhancement of contractions until birth occurs.
Conclusion
Wrap-up of the first recorded lecture.
Reminder to refer to other recordings for the rest of the course content.