Anatomy & Physiology 1 - Body Structures & Anatomical Positions
Outcome 1: Body Structures & Anatomical Positions
01. Identify the body functions necessary to maintain life
Introduction to Anatomy and Physiology
Anatomy: The study of the body's structure and how its parts are arranged (Shape/Form). This includes looking at large parts (Gross Anatomy) and very tiny parts (Microscopic Anatomy, like cells and tissues).
Physiology: The study of how the human body works (Function).
The body constantly tries to achieve homeostasis, which is a stable, balanced condition inside the body, necessary for optimal health and survival.
Levels of Structural Organization
Chemical Level: Basic elements (like C, H, O, N) form chemical structures called molecules (like proteins, sugars, DNA).
Cellular Level: Molecules gather to form cells, which are the fundamental living units (e.g., muscle cells, brain cells).
Tissue Level: Similar cells group together to perform one specific function (There are four types: Epithelial, Connective, Muscular, Nervous).
Organ Level: Two or more different types of tissues work together to do complex tasks (e.g., stomach, heart).
System Level: Groups of related organs work together for a major purpose (e.g., Digestive System, how blood moves).
Organismal Level: All systems work together to create a complete living person or animal.
Functions of Life
Metabolism: All the chemical reactions happening inside the body's cells that create energy and keep the body running.
Anabolism: Processes that use energy (ATP) to build large, complex molecules from smaller ones (e.g., building protein for muscles).
Catabolism: Processes that release energy (ATP) by breaking down large molecules into smaller ones (e.g., digesting food).
Responsiveness (Excitability): The ability to notice changes (stimuli) both inside and outside the body and react to them properly.
Movement: Includes motion on all scales: moving the whole body, moving internal organs (like the heart), moving cells, and moving materials within cells.
Development:
All changes that happen from conception until death.
Includes Differentiation: When general cells change into specific cells that have unique jobs (specialization).
Growth: Getting bigger by increasing the size of cells, increasing the number of cells, or increasing the material between cells (extracellular matrix).
Reproduction: Making new cells for repair/growth, or creating a new individual.
02. Discuss the role of homeostasis in healthy functioning of the body
Homeostasis
The key feature of life; keeping the body's internal environment relatively balanced and stable (equilibrium), essential for health.
It is a Dynamic condition, meaning things inside the body constantly change but stay within a safe, narrow range.
Controlled conditions (variables): Specific parameters that are constantly tracked (e.g., body temperature, blood sugar, blood pressure).
Set point: The ideal or normal range for a controlled condition.
Life depends on maintaining this narrow range; failing to do so leads to sickness or death.
Disruption of Homeostasis: Stress that causes an internal imbalance. If the disruption is severe or lasts too long, medical help is needed to fix the balance.
The body regulates balance using sophisticated feedback systems that continuously monitor and adjust processes.
Components of Feedback Systems
Receptors (Sensors): Monitoring devices that notice changes in the controlled condition (stimulus). They change the signal into input data (signals) and send it through afferent pathways (input) to the control center.
Control Center (Integration Center): Usually the brain or a specific gland. It receives the signal, compares it to the ideal set point, and decides what response is needed. It sends instructions through efferent pathways (output) to the effectors.
Effectors: Body parts (muscles or glands) that get instructions from the Control Center and make a change (the response) to fix the problem.
Types of Feedback Systems
Negative Feedback Systems: The most common type. They work to stop or reverse the original change, bringing the condition back toward the set point.
Example 1: Regulating blood pressure (BP). If BP rises, sensors signal the brain, which tells the heart to slow down. This lowers BP, restoring balance.
Example 2: Thermoregulation. If body temperature gets too high, the brain signals sweat glands to produce sweat, causing cooling and bringing the temperature back to normal.
Positive Feedback Systems: Less common. They increase or strengthen the original change, moving the condition further away from the set point until a specific event ends the loop.
Example: Childbirth. Contractions stretch the cervix, which signals the brain to release oxytocin. Oxytocin makes contractions stronger, continuing the cycle until the baby is born, which stops the stretching and the loop.
03. Describe the anatomical positions and planes of the human body
Importance of Standard Medical Terminology
Standard terminology is essential for studying the body. Using consistent rules for direction and position reduces confusion.
Standard definitions ensure that descriptions are accurate, regardless of whether the person is standing, sitting, or lying down.
Anatomical Position (Standard)
The body is standing straight, head level, facing forward.
Arms are straight at the sides with palms facing forward (supination).
Legs are straight, feet are slightly apart, with toes pointing forward.
Note: "Right" and "Left" always refer to the subject's (patient’s) right and left sides.
Variation of Positions:
Supine position: Lying face up (on the back).
Prone position: Lying face down (on the abdomen).
Directional Terms: Used to accurately explain where one structure is located compared to another.
Distinctions: Medial (near the middle line) vs. Median (exactly on the body's middle line).
Directional Terms include:
Superior (Cranial/Cephalic): Closer to the head or the upper part of the structure. Example: The heart is superior to the diaphragm.
Inferior (Caudal): Away from the head or toward the bottom part (tail). Example: The stomach is inferior to the lungs.
Anterior (Ventral): Toward the front of the body or the belly side. Example: The sternum is anterior to the heart.
Posterior (Dorsal): Toward the back side of the body. Example: The spine is posterior to the windpipe.
Medial: Nearest the center line of the body. Example: The ulna is medial to the radius.
Lateral: Away from the center line; toward the sides. Example: The lungs are lateral to the heart.
Intermediate: In between two other structures (one closer to the middle and one farther).
Proximal: Closer to where a limb attaches to the trunk (used only for arms and legs).
Distal: Further away from where a limb attaches (used only for arms and legs).
Superficial (External): Closer to the body's surface.
Deep (Internal): Further away from the body's surface. Example: Bone is deep to skin and muscle.
Ipsilateral: On the same side of the body.
Contralateral: On the opposite side of the body.
Body Planes: Imaginary flat surfaces used to cut the body or organs into specific views for study.
Main Anatomical Planes:
Sagittal Plane: A vertical cut that divides the body into left and right parts. If the cut makes equal halves, it is the Median/Midsagittal Plane. If the halves are unequal, it's a Parasagittal Plane.
Frontal Plane (Coronal Plane): A vertical cut that divides the body into front (anterior) and back (posterior) parts.
Transverse Plane (Horizontal or Axial Plane): A horizontal cut that divides the body into upper (superior) and lower (inferior) sections.
Oblique Plane: Sections or cuts made diagonally or at an angle relative to the main planes.
Body Sections: Specific slices viewed via imaging after cutting along a plane.
Sagittal Section: A slice resulting from a cut along any sagittal plane.
Frontal (Coronal) Section: A slice resulting from a cut along any coronal plane.
Transverse Section: A slice resulting from a cut along any horizontal plane.
Oblique Section: A slice resulting from a diagonal cut across the body or organ.
Review Quizzes
Quiz Items for Terminology and Planes:
The elbow is
Distal
to the shoulder. (Farthest from the anchor point)
The ribs are
Lateral
to the sternum. (To the sides)
The heart is
Medial
to the 2 lungs. (Nearest the center line)
The ribs are
Superior
to the lungs. (Above)
The ankle is
Proximal
to the foot. (Closer to the anchor point)
The thumb is
Lateral
to the pinkie finger. (Further from the center line)
The abdominal muscles are
Anterior
to the back muscles. (In front of)
The head is
Superior
to the neck. (Above)
The vertebrae are
Posterior
to the sternum. (Behind)
04. Identify the major body cavities and subdivisions, and the major organs contained within each
Body Regions (Regional Anatomy)
Defines specific areas commonly used by doctors for examinations or describing pain.
Axial Region: Head, Neck, and Trunk (Chest, Abdomen, and Pelvis).
Appendicular Region: Arms and Legs.
Main regions include:
Head (Cranium/Cephalic)
Neck (Cervical)
Chest (Thoracic)
Abdomen
Pelvis
Upper limb (Arm, Forearm, Wrist)
Lower limb (Thigh, Leg, Ankle)
Back (Dorsal)
Detailed Body Regions (Selected Terms): Specific terms for locations like:
Frons (forehead), Oris (mouth), Mentis (chin), Axilla (armpit), Brachial (arm), Antecubital (front of elbow), Plantar (sole of foot), Popliteal (back of knee), Gluteal (buttock), Pubic, Inguinal (groin), Orbital (eye).
Body Cavities
Body cavities are internal spaces that hold, protect, and support internal organs (viscera).
Dorsal Body Cavity: Located on the back side of the body.
Cranial Cavity: Surrounded by the skull, contains the brain.
Vertebral Canal (Spinal Cavity): Formed by the spine, contains the spinal cord and the start of the spinal nerves.
Ventral Body Cavity: Located in the front of the body. It holds the Thoracic and Abdominopelvic cavities, which are separated by the diaphragm (a large muscle).
Thoracic Cavity: - Above the diaphragm. Surrounded by the ribcage.
Subdivisions:
Pleural Cavities (2 total): Each surrounding a lung. Lined by pleural membranes.
Mediastinal Cavity (Mediastinum): The center space between the two lungs. This area contains the pericardial cavity, heart, esophagus, windpipe (trachea), and major blood vessels.
Pericardial Cavity: Specifically contains the heart. Lined by pericardial membranes.
Abdominopelvic Cavity: Below the diaphragm.
Abdominal Cavity (Upper portion): Contains the major digestive organs
—the stomach, spleen, liver, gallbladder, small intestine (most of it), and most of the large intestine.
Pelvic Cavity (Lower portion): Contained within the hip bones. Contains the urinary bladder, portions of the large intestine (sigmoid colon and rectum), and parts of the reproductive organs.
Subdivisions of the Abdominopelvic Cavity
Quadrantal pattern (Clinical): Used clinically to quickly locate problems. Divides the abdomen into four sections (Upper Right, Upper Left, Lower Right, Lower Left) using imaginary lines that meet at the belly button.
Nine region pattern (Anatomical): Divides the abdomen more precisely using two horizontal lines and two vertical lines.
Right Hypochondriac Region
Epigastric Region (Above the stomach)
Left Hypochondriac Region
Right Lumbar (or Flank) Region
Umbilical Region (Around the navel)
Left Lumbar (or Flank) Region
Right Inguinal (or Iliac) Region
Hypogastric (or Pubic) Region (Below the stomach area)
Left Inguinal (or Iliac) Region
05. Describe the membranes of the ventral body cavity