Anatomy and Physiology Overview

Anatomy and Physiology

• Anatomy refers to the study of body structure and shape, including relationships between body parts.
• Gross anatomy deals with large, visible structures, while microscopic anatomy involves very small structures observable only through microscopes.
• Physiology focuses on how body parts function and work together.

Levels of Structural Organization

• Atoms are the tiny building blocks of matter that form molecules.
• Cells represent the smallest living units and exhibit immense variety in shape and size.
• Tissues are groups of similar cells working together to perform a common function, categorized into four basic tissue types.
• An organ is a structure made of two or more tissue types that works to perform specific bodily functions.
• Organ systems consist of groups of organs that cooperate to achieve a common goal.
• An organism is the entire living body, representing the highest level of structural organization.

Human Body Systems

• The integumentary system encompasses the skin, providing waterproofing, cushioning, protection, excretion of salts, and vitamin D synthesis.
• The skeletal system includes bones and cartilage, supporting organs, enabling movement, producing blood cells, and storing minerals.
• The muscular system, made up of skeletal muscles, facilitates movement, manipulation of the environment, locomotion, and heat production.
• The nervous system acts as the body’s fast-acting control system, responding to changes through muscles and glands.
• The endocrine system produces hormones, controlling growth, reproduction, and metabolism, involving glands like the pituitary and thyroid.
• The cardiovascular system circulates blood, delivering oxygen, nutrients, and waste products; the heart is its pump.
• The lymphatic system ensures fluid balance and immune defense by returning leaked fluids to the bloodstream and housing white blood cells.
• The respiratory system maintains blood oxygen levels and removes carbon dioxide via gas exchange in the lungs.
• The digestive system breaks down food into absorbable units, redistributing nutrients while removing indigestible waste.
• The urinary system eliminates nitrogenous wastes while regulating water, electrolytes, and blood pH.
• The reproductive system's primary function is producing offspring, with separate male and female systems facilitating this.

Functions Essential for Life

• Maintaining boundaries keeps body compartments distinct.
• Movement encompasses physical activities promoted by the muscular system, aided by the skeletal system.
• Responsiveness involves sensing and reacting to environmental changes, primarily managed by the nervous system.
• Digestion converts food into absorbable molecules for cellular energy and building.
• Metabolism includes all chemical reactions within cells and is regulated by hormones.
• Excretion involves removing wastes from the body.
• Reproduction refers to producing offspring, occurring at both cellular and organismal levels.
• Growth denotes an increase in size, generally reflected in cell number.

Survival Needs

• Critical survival needs include nutrients, oxygen, water, stable body temperature, and atmospheric pressure.
• Nutrients obtained through diet are vital for energy and cell creation: carbohydrates provide energy, proteins form structures, and fats act as cushions and fuel.
• Water is vital and serves as a solvent for secretions and excretions, constituting the most abundant chemical in the body.
• Oxygen is crucial for energy-releasing chemical reactions.
• Body temperature must be maintained at about 37°C (98.7°F) for optimal metabolic function.
• Atmospheric pressure is the force that surrounds the body, crucial for respiratory processes.

Homeostasis

• Homeostasis is the body's capability to maintain a stable internal environment despite external changes, characterized by dynamic equilibrium.
• Receptors monitor environmental changes and send feedback to a control center, which analyzes the data to determine a response.
• Effectors are mechanisms that enact responses to stimuli, progressing through feedback loops to restore balance.
• Negative feedback mechanisms reduce stimulus intensity, stabilizing bodily functions, whereas positive feedback mechanisms enhance responses, crucial in processes like blood clotting and childbirth.
• Homeostatic imbalance indicates a disruption in equilibrium, often associated with diseases, especially as physiological regulation declines with aging.

Anatomical Terminology

• Anatomical position describes the standard orientation for observations, with the body standing erect, feet parallel, arms at sides, and palms facing forward.
• Directional terms include superior (above), inferior (below), anterior (front), posterior (back), medial (toward the midline), lateral (away from the midline), proximal (near attachment point), distal (far from attachment point), superficial (toward the surface), and deep (away from the surface).

Body Cavities and Planes

• The dorsal body cavity is divided into the cranial cavity (housing the brain) and spinal cavity (surrounding the spinal cord).
• The ventral body cavity contains structures within the chest and abdomen.
• Sections made through the body can follow various planes, including sagittal (divides left and right), midsagittal (equal left and right parts), frontal (divides front and back), and transverse (divides upper and lower).

Explore the foundational concepts of anatomy and physiology, including the levels of structural organization within the human body. This quiz covers gross and microscopic anatomy, as well as the various organ systems and their functions.