Anatomy and Physiology Fundamentals

Anatomy and Physiology

• Anatomy investigates the body's structure.
• Physiology studies the body's processes and functions.
• Human physiology studies the human organism.
• Systemic physiology studies body organ-systems.
• Cellular physiology studies body cells.
• Understanding anatomy and physiology helps in understanding the body's responses to stimuli, environmental changes/cues, diseases, and injuries.

Types of Anatomy

• Systemic anatomy studies body organ-systems.
• Regional anatomy studies body regions.
• Surface anatomy studies external features.
• Anatomical imaging involves using technologies like x-rays, ultrasound, and MRI.

Structural and Functional Organization

• The levels of organization from chemical to organism are: chemical, cellular, tissue, organ, organ system, and organism

Chemical Level

• The chemical level is the smallest level of organization.
• Atoms form chemical bonds and molecules.

Cellular Level

• Cells are the basic units of life.
• Cells contain compartments and organelles.
• Examples of organelles include mitochondria and the nucleus.

Tissue Level

• Tissues are groups of cells with similar structures and functions, plus extracellular substances they release.
• The four broad types of tissues are: epithelial, connective, muscular, and nervous.

Organ Level

• Organs are composed of two or more tissue types working together to perform specific functions.
• Examples of organs are the stomach, heart, liver, ovary, bladder, and kidney.

Organ-System Level

• Organ systems are groups of organs contributing to certain functions.
• The digestive and reproductive systems are examples of organ systems.

Organism Level

• Organisms consist of all organ systems working together.
• An organism includes associated microorganisms such as intestinal bacteria.

Characteristics of Life

• Organization involves functional interrelationships between parts.
• Metabolism encompasses all chemical and physical changes sustaining an organism.
• Responsiveness is the ability to sense and respond to environmental changes.
• Growth is the ability to increase in size through cell enlargement or increased extracellular material.
• Development involves changes in form and size.
• Development also involves changes in cell structure and function from generalized to specialized, which is called differentiation.
• Reproduction includes the formation of new cells or organisms.
• Reproduction includes generation of new individuals and tissue repair.

Homeostasis

• Homeostasis is the maintenance of a consistent internal environment despite external or internal fluctuations.
• Variables are measures of body properties that may change in value.
• Examples of variables include: body temperature, heart rate, blood pressure, blood glucose levels, blood cell counts, and respiratory rate.
• Normal range refers to the normal extent of increase or decrease around a set point.
• Set point is the normal or average value of a variable
• Over time, body temperature fluctuates around a set point.
• Set points for some variables can be temporarily adjusted depending on body activities as needed.
• Fever may cause temporary adjustment of body temperature.
• Exercise may cause temporary adjustment of heart rate, blood pressure, and respiratory rate.
• Negative feedback is the primary mechanism for maintaining homeostatic regulation.
• Negative feedback involves; detection of deviation from set point and correction by reversing the deviation to return to the set point, or normal range.

Components of Feedback

• The receptor detects changes in a variable.
• The control center receives the receptor signal and establishes the set point.
• The control center sends a signal to the effector.
• The effector directly causes a change in the variable.
• Positive feedback mechanisms occur when the initial stimulus enhances the response and causes progressive deviation away from the set point/normal range.
• Positive feedback not directly used for homeostasis.
• Childbirth is an example of needed positive feedback.
• Positive feedback is generally associated with injury or disease.
• Negative feedback mechanisms are unable to maintain homeostasis.

Anatomical Position

• The anatomical position is a person standing erect with face and palms forward.
• Relational descriptions are based on the anatomical position, regardless of body orientation.

Directional Terms

• Superior means above.
• Inferior means below.
• Anterior means front (also ventral.)
• Posterior means back (also dorsal).
• In four-legged animals, the belly is the ventral and the back is the dorsal, corresponding to anterior and posterior in humans.
• Medial means close to midline.
• Lateral means away from midline.
• Proximal means close to the point of attachment.
• Distal means far from the point of attachment.
• Superficial defines structures close to the surface.
• Deep defines structures toward the interior of the body.

Body Regions

• The upper limbs include the upper arm, forearm, wrist, and hand.
• The lower limbs include the thigh, lower leg, ankle, and foot.
• The central region includes the head, neck, and trunk.

Body Planes

• The sagittal plane separates the body into right and left parts.
• The median plane, a sagittal plane along the midline divides the body into equal left and right halves.
• The transverse plane is a horizontal plane separating the body into superior and inferior parts.
• The frontal plane is a vertical plane that separates the body into anterior and posterior parts.

Body Cavities

• The dorsal body cavity encloses the organs of the nervous system.
• The cranial cavity contains the brain.
• The vertebral canal contains the spinal cord.
• The ventral body cavity contains the majority of internal organs (viscera).
• The thoracic cavity includes space within the chest wall and diaphragm, and contains the heart, lungs, thymus gland, esophagus, and trachea.
• The mediastinum is the space between lungs, and contains the heart, thymus gland, esophagus, and trachea.
• The abdominopelvic cavity contains the abdominal and pelvic cavities.
• The abdominal cavity is the space between the diaphragm and pelvis and contains the stomach, intestines, liver, spleen, pancreas, and kidneys.
• The pelvic cavity is the space within the pelvis and contains the urinary bladder, reproductive organs, and part of the large intestine.

Serous Membranes

• Serous membranes line trunk cavities, cover organs in the ventral body cavity.
• Visceral serous membrane covers organs.
• Parietal serous membrane lines the walls of cavities.
• The cavity is a fluid-filled space between the membranes.
• Pericardial cavity surrounds the heart, and the membrane is called the Pericardium.
• The Pleural Cavity surrounds the lungs, and the membrane is called the Pluera
• The Peritoneal Cavity surrounds the abdominopelvic cavity and its organs, the membrane is called the Peritoneum.

Pericardium

• Visceral pericardium covers the heart.
• Parietal pericardium is thick and fibrous.
• The pericardial cavity reduces friction.

Pleura

• Visceral pleura covers the lungs.
• Parietal pleura lines inner wall of thorax.
• The pleural cavity reduces friction and adheres lungs to the thoracic wall.

Peritoneum

• Visceral covers and anchors organs, contains double layers called mesenteries.
• Parietal lines inner wall of abdominopelvic cavity.
• The peritoneal cavity reduces friction.

Explore the relationship between anatomy and physiology, understanding their importance in comprehending the body's responses. Learn about different types of anatomy, such as regional and clinical. Review the levels of structural organization and the four broad tissue types found in the human body.