biology 20 unit d

Tissue

Group of similar cells performing a function.

Organ

Structure made of tissues performing specific tasks.

Organ system

Group of organs working together for a function.

Organism

Individual living entity, e.g., human.

Arteries

Blood vessels carrying blood away from the heart.

Characteristics of arteries

Thick walls, elastic to withstand pressure.

Pulse

Rhythmic expansion in arteries, felt at specific points.

Arterioles

Small branches of arteries leading to capillaries.

Vasodilation

Widening of blood vessels to increase blood flow.

Vasoconstriction

Narrowing of blood vessels to reduce blood flow.

Aneurysm

Abnormal bulging in a blood vessel wall.

Arteriosclerosis

Hardening and thickening of arterial walls.

Capillaries

Microscopic vessels facilitating exchange of substances.

Function of veins

Return deoxygenated blood to the heart.

Characteristics of veins

Thinner walls, contain valves to prevent backflow.

Pericardium

Membrane protecting the heart from friction.

Circulatory system

Composed of cardiovascular and lymphatic systems.

Cardiac output

Volume of blood pumped by the heart per minute.

Systolic blood pressure

Pressure during heartbeats when ventricles contract.

Diastolic blood pressure

Pressure when heart is at rest between beats.

Lymph nodes

Filter lymph and produce immune cells.

Components of blood

Red blood cells, white blood cells, platelets.

Erythrocytes

Red blood cells transporting oxygen in blood.

Leukocytes

White blood cells defending against infections.

Platelets

Cell fragments aiding in blood clotting.

Functions of blood

Distribution, regulation, and protection of body.

Blood typing

Classification based on antigens on red blood cells.

Rh factor

Antigen determining positive or negative blood type.

First line of defense

Skin and mucous membranes preventing pathogen entry.

Second line of defense

Inflammatory response and phagocytosis against pathogens.

Third line of defense

Adaptive immunity involving T-cells and B-cells.

Types of white blood cells

Neutrophils, lymphocytes, monocytes, eosinophils, basophils.

T-cells

Types include helper, cytotoxic, memory, and regulatory.

B-cells

Produce antibodies to neutralize pathogens.

Antibiotics

Medications targeting bacteria, not viruses.

Autoimmune diseases

Immune system attacks body's own cells.

Allergies

Immune response to harmless substances.