Key Concepts in Human Anatomy and Physiology

Spleen

A fist-sized, soft, spongy organ located in the upper left part of the abdomen, under the left rib cage and above the stomach.

Hormones

Chemical messengers produced by endocrine glands in the body.

Lymph Nodes

Small, bean-shaped glands that are part of the lymphatic system. They are distributed throughout the body and are crucial in filtering lymph fluid and fighting infections.

Fever

It's a sign that your body is fighting an infection or illness. Fevers are often triggered by infections, either viral or bacterial. They can also be caused by other factors like autoimmune diseases, certain medications, or even heatstroke.

Adaptive defense

A part of the body's immune system that develops after exposure to a specific pathogen or antigen.

Erythrocyte

Red blood cells.

Leukocyte

White blood cells.

Septum

The nasal septum is a midline structure in the nose that separates the two nasal cavities. It's composed of both bone and cartilage and is covered by a mucous membrane.

Plasma

The liquid component of blood that makes up about 55% of its volume.

Aorta

The largest artery of the body, and carries blood from the heart to the circulatory system.

Hypertension

A condition where the force of blood against the artery walls is consistently too high.

Tonsils

Two round, fleshy masses in the back of your throat (pharynx).

Arteries

Blood vessels that carry oxygen-rich blood away from the heart to the rest of the body.

Veins

Blood vessels that carry oxygen-rich blood away from the heart to the rest of the body.

Capillaries

Delicate blood vessels (tubes that hold blood) throughout your body.

Universal donor

A person of blood group O, who can in theory donate blood to recipients of any ABO blood group.

Universal recipient

A person of blood group AB, who can in theory receive donated blood of any A, B, AB or O blood group.

Innate body defense

The innate immune system is the body's first line of defense, providing a rapid, non-specific response against pathogens.

Parietal lobe

A region of the brain located in the upper, rear part of the head, responsible for processing sensory information, particularly touch, temperature, pressure, and pain. It also plays a crucial role in spatial awareness, navigation, and integrating information from other brain areas.

Temporal lobe

Located on the sides of the head, and plays a crucial role in processing auditory information, language, and certain aspects of visual memory. It is also involved in processing emotions, particularly those related to smell, taste, and touch.

Frontal lobe

The frontal lobe is the largest of the brain's four main lobes, located at the front of the brain and responsible for a wide range of cognitive and motor functions. It plays a crucial role in personality, behavior, and higher-level thinking processes.

Occipital lobe

The occipital lobe is a part of the brain located at the back of the head, behind the parietal and temporal lobes. It plays a crucial role in processing visual information.

Valves

Valves primarily function to control the flow of fluids and blood by either stopping, starting, regulating, or changing the direction of flow.

Stomach acid

A digestive fluid produced by the stomach lining that contains hydrochloric acid (HCl). It's a highly acidic fluid with a pH between 1 and 3, essential for breaking down food, activating digestive enzymes, and killing harmful bacteria.

Inflammatory Response

The body's natural reaction to injury or infection, involving the activation of the immune system to protect against harm and initiate healing.

Viruses

A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea.

Antigens

Substances that trigger an immune response in the body, typically by causing the production of antibodies.

Fungi

A fungus is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms.

Pollen

A fine powdery substance, typically yellow, consisting of microscopic grains. Each grain contains a male gamete that can fertilize the female ovule, to which pollen is transported by the wind, insects, or other animals.

Brainstem

Connects your brain to your spinal cord.

Phagocytic cells

A type of white blood cell that engulf and destroy harmful foreign particles, including bacteria, dead cells, and debris, to protect the body.

Peyer's Patches

Specialized collections of lymphatic tissue found in the mucosa of the small intestine.

Pulmonary

The lungs.

Systemic

A branch of anatomy that studies the body's structure by examining its organ systems. It focuses on the arrangement, composition, and function of each system, as well as how they interact with one another.

Epicardium

A serous membrane that forms the innermost layer of the pericardium and the outer surface of the heart.

Myocardium

The thin, smooth membrane which lines the inside of the chambers of the heart and forms the surface of the valves.

Endocardium

The thin, smooth membrane which lines the inside of the chambers of the heart and forms the surface of the valves.

Systolic

The pressure in your arteries when your heart is at rest, filling with blood between beats. It's the bottom number in a blood pressure reading, and it indicates the pressure when your heart is relaxing.

Diastolic

The pressure in your arteries when your heart is at rest, filling with blood between beats. It's the bottom number in a blood pressure reading, and it indicates the pressure when your heart is relaxing.

Saliva

Watery liquid secreted into the mouth by glands, providing lubrication for chewing and swallowing, and aiding digestion.

Eardrum

A thin, cone-shaped membrane located at the end of the ear canal. It's a crucial part of the hearing process, separating the outer ear from the middle ear.

Ovary

One of a pair of female reproductive glands responsible for producing eggs and the female hormones estrogen and progesterone.

Kidneys

Kidneys remove waste products, toxins, and excess fluid from the blood, producing urine.

Thyroid Gland

A small, butterfly-shaped endocrine gland located in the neck, just below the Adam's apple. It produces thyroid hormones that regulate metabolism, growth, and development.

Optic Nerve

A pathway to send visual information from the eye to the brain.