Anatomy and Physiology

Anatomy and Physiology

• Anatomy involves the body's structure.
• Physiology involves the body's functions.
• Systemic physiology studies functions of body systems.
• Cellular physiology studies functions at the cellular level.

Importance of Anatomy and Physiology

• Understanding anatomy and physiology increases our understanding of how the body functions and reacts.
• Provides insight into how the body responds to stimuli.
• Provides insight into how the body adapts to environmental changes.
• Provides insight into how the body heals from diseases and injuries.
• It shows how the body maintains stability under fluctuating conditions.

Types of Anatomy

• Systemic anatomy studies body systems.
• Regional anatomy studies body regions and is common in medical schools.
• Surface anatomy studies external features, such as bone projections.
• Anatomical imaging uses technologies like X-rays, ultrasound, and MRI.

Structural Organization

• The body has six levels of organization beginning with chemical make up to forming an entire organism.
• Chemical level: the most basic level, including atoms and molecules.
• Cellular level: cells, the basic units of life, contain compartments and organelles like mitochondria and the nucleus.
• Tissue level: groups of similar cells performing specific functions, including epithelial, connective, muscular, and nervous tissues.
• Organ level: two or more tissue types working together to perform specific functions, such as the stomach, heart, liver, ovary, bladder, and kidney.
• Organ system level: groups of organs contributing to a particular function, such as the digestive and reproductive systems.
• Organism level: all organ systems working together, including associated microorganisms like intestinal bacteria.

Characteristics of Life

• Organization: functional interrelationships between parts of the body,
• Metabolism: chemical and physical changes that help sustain an organism while acquiring and using energy.
• Responsiveness: the ability to sense and respond to internal and external environmental changes.
• Growth: the ability to increase in size.
• Development: changes in form, size, cell structure, and function like cell specialization (differentiation).
• Reproduction: formation of new cells or organisms for growth, repair, and generation.

Homeostasis

• Homeostasis is maintaining a stable internal environment.
• Variables are body properties that can change, like temperature, glucose levels, heart rate, blood cell counts, blood pressure, and respiratory rate.
• Normal range: the extent of increase or decrease around a set point.
• Set point: the normal value of a variable.
• Set points can change temporarily based on activities like fever from illness, or exercise increasing heart rate, blood pressure, and respiratory rate.

Negative Feedback

• It is a mechanism that maintains homeostasis involving opposing actions.
• Detection: noticing deviations from a set point.
• Correction: reversing deviations to return to the set point within a normal range.

Components of Negative Feedback

• Receptor: detects changes in a variable and monitors body temperature
• Control center: receives signals from the receptor and compares to the set-point
• Effector: directly causes changes in a variable

Positive Feedback

• Causes deviation away from a set point, outside the normal range.
• Not directly used for homeostasis.
• Can occur under normal conditions such as childbirth.
• Commonly associated with injury or disease.

Anatomical Position

• The anatomical position is standing erect with the face and palms forward.
• Relational descriptions are based on anatomical position.
• Supine: lying face up.
• Prone: lying face down.

Directional Terms

• Superior: above.
• Inferior: below.
• Anterior (ventral): front.
• Posterior (dorsal): back.
• Medial: toward the midline.
• Lateral: away from the midline.
• Proximal: close to the point of attachment.
• Distal: far from the point of attachment.
• Superficial: close to the body's surface.
• Deep: away from the body's surface.

Body Planes

• Sagittal plane: vertical plane dividing the body into anterior and posterior parts.
• Midsagittal plane: divides the body into equal left and right halves along the midline.
• Transverse (horizontal) plane: divides the body into superior and inferior parts.
• Frontal (coronal) plane: vertical plane dividing the body into anterior and posterior parts.

Planes of Section Through an Organ

• Longitudinal section: lengthwise cut along the long axis of an organ.
• Transverse Section: A cross-section cut at a right angle to the long axis of an organ
• Oblique Section: A diagonal cut across the long axis of an organ

Body Regions

• Upper limbs: upper arm, forearm, wrist, and hand.
• Lower limbs: thigh, lower leg, ankle, and foot.
• Central region: head, neck, and trunk.

Body Cavities

• Thoracic cavity: space within the chest wall and diaphragm, containing the heart, lungs, esophagus and thymus gland.
• Mediastinum: space between the lungs, containing the heart, thymus gland, esophagus, and trachea.
• Abdominal cavity: space between the diaphragm and pelvis, containing the stomach, intestines, liver, spleen, pancreas, and kidneys.
• Pelvic cavity: space within the pelvis, containing the urinary bladder, reproductive organs, and part of the large intestine.

Serous Membranes

• Line trunk cavities and cover organs.
• Visceral serous membrane: covers organs.
• Parietal serous membrane: lines the cavity wall.
• Cavity: space between the membranes, filled with fluid.
• Pericardium: membrane around the heart.
• Pleura: membrane around the lungs.
• Peritoneum: membrane around the abdominopelvic cavity and its organs.
• Pericardial cavity: reduces friction and contains a pericardial fluid.
• Pleural cavity: reduces friction between the lungs and the inner wall of the thorax.
• Peritoneal cavity: reduces friction within the abdominopelvic cavity.