Human Body Systems and Levels of Organization

A comprehensive set of vocabulary flashcards covering the levels of organization, tissue types, and major organ systems of the human body based on lecture notes.

Cells

The basic unit of structure and function in living things, such as a Red Blood Cell.

Tissues

A group of similar cells that perform the same function, such as Muscle Tissue.

Organs

Groups of different types of tissue that perform a specific job, such as the Liver.

Organ Systems

Groups of organs that work together to perform a specific purpose in the human body, such as the Digestive System.

Epithelial tissue

Tissue that covers body surfaces and lines hollow organs; examples include skin and the outer layer of the heart.

Connective tissue

Tissue that protects, supports, and binds organs; examples include tendon, ligament, bone, and fat.

Muscular tissue

Tissue that generates the physical force needed to make body structures move; examples include biceps, triceps, and pectorals.

Nervous tissue

Tissue that detects changes in the body and responds by generating nerve impulses; found in large quantities in the brain and spinal cord.

Ligaments

Connective tissue that connects bone to bone.

Tendon

Connective tissue that connects muscle to bone.

Digestive System

System responsible for converting food particles into simpler molecules that can be absorbed into the bloodstream.

Mouth

Organ used to chew and grind up food where saliva begins chemical breakdown.

Esophagus

The pipe connecting the mouth to the stomach.

Stomach

Organ that secretes a strong acid with a pH of $2$ to break down food through chemical and mechanical digestion.

Chyme

The name for food once it is broken down in the stomach and mixed with digestive juices.

Liver

Organ that produces bile, which breaks down fats in foods.

Small Intestine

Organ that absorbs nutrients from food; its length is a reason for its high absorption capacity.

Large Intestine

Organ that removes water from waste and gets it ready for excretion.

Stomach Mechanical Digestion

The process where the stomach breaks up food by churning and grinding using muscles.

Respiratory System

System that provides the body with a fresh supply of oxygen for cellular respiration and removes carbon dioxide.

Trachea

The ‐windpipe‐ or what connects the pharynx to the lungs.

Epiglottis

A flap of tissue that covers the trachea when you swallow to prevent food from entering.

Alveoli

Tiny air sacs located in the lungs.

Diaphragm

A muscle that allows you to breathe by pulling air into the lungs.

Circulatory System

System that delivers oxygenated blood to various cells and organ systems for cellular respiration.

Heart

The major muscle of the circulatory system that pumps blood through four chambers: two ventricles and two atria.

Arteries

Blood vessels that carry oxygenated blood away from the heart to the major organs.

Veins

Blood vessels that carry blood back to the heart away from the major organs.

Capillaries

Small blood vessels where gas exchange occurs.

Hemoglobin

A substance contained in red blood cells that carries oxygen.

Nervous System

System that coordinates the body’s response to changes in environment and regulates all body functions.

Brain

The control center of the body where all processes are relayed through.

Skeletal System

System that provides structure and support; bones in this system also generate new blood cells in the marrow.

Bone Marrow

The location in bones where new blood cells are generated.

Immune System

System that removes infectious diseases and other pathogens from the human body.

White Blood Cells

Cells that fight infection by recognizing antigens and creating antibodies to remove them.

Skin

Also called the integumentary system, it serves as the body’s first line of defense.