Biology 2201: Unit 3 - Test 2

Circulatory system

Carries substances around the body. Both good things and bad things are carried to where they need to go. Also involved in immunity.

Pulmonary circulation

Takes deoxygenated blood from the heart through the lungs and to be supplied with oxygen.

Systemic circulation

Takes oxygenated blood from the heart to the body and then back to the heart.

Cardiac circulation

Blood circulation throughout the heart.

Atria

Collecting chambers. Receives blood from lungs and body, pump it into ventricles. Right side receives deoxygenated blood from the body. Left side receives oxygenated blood from the lungs.

Ventricles

Thick, muscular chambers that pump blood away from the heart. Right side pumps deoxygenated blood to the lungs. Left side pumps blood to the body.

Bicuspid valve

Regulates flow between left atria and left ventricle.

Tricuspid valve

Regulates flow between right atria and the right ventricle.

Aortic valve

Regulates flow from the left ventricle into the aorta.

Aorta

Largest artery of the body. Carries blood from the heart to the rest of the body.

Septum

Muscular wall of the heart that divides it into two halves.

Pulmonary vein

Returns oxygenated blood from the lungs to the heart. Only vein in the body to carry oxygenated blood.

Pulmonary artery

Carries deoxygenated blood from the heart to the lungs. Only artery in the body to carry deoxygenated blood.

Arteries

Any blood vessel that carries blood away from the Heart. Smaller ones are known as arterioles. Are made of three layers. Outer – connective tissue and elastic fibers. Middle – smooth muscle and elastic fibers. Inner – single layer of epithelial cells used to reduce friction.

Veins

Blood vessels that return blood to the heart. Smaller ones are known as venules. Contain the same three structural layers as arteries. Layers are thinner and more flexible.

Capillaries

Incredibly small blood vessels that connect the circulatory system to body tissues. Site of nutrient, gas, and waste exchange. Are one cell layer thick with an average diameter 8 μm. Small size allows for the diffusion of nutrients, gas, and wastes.

Sinoatrial node

The pacemaker, stimulates both atria by producing an electrical impulse.

Atrioventricular node

Transmits the impulse, causing the two ventricles to contract.

Plasma

Fluid portion of blood. Carries blood cells, nutrients, and wastes. Clear fluid composed of water, dissolved substances, and proteins. Has several functions

Red blood cells

Erythrocytes. On average, people have between 4.5 – 5.5 million per milliliter of blood. Are specialized for oxygen transport. Oxygen transport made possible by hemoglobin. Is 45% of our total blood's volume.

White blood cells

Leucocytes. Function to protect the body from infections. Numbers increase during infection. There are two main types

Platelets

Are not cells, but are fragments of bone marrow cells. Play an important role in blood clotting.

Heart Rate

the number of times the heart beats within a certain time period.

Blood Pressure

is created by the force of blood pushing against the walls of blood vessels (arteries) as it is pumped by the heart. The higher the pressure, the harder the heart has to pump.

Systolic

Measures the pressure in your arteries when your heart beats. Normal is 120.

Diastolic

Measures the pressure in your arteries when your heart rests between beats. Normal is 80.

Immune system

Functions to provide the body with the ability to fight infection through the production of antibodies and cells that attack pathogens. It helps to maintain homeostasis by recognizing and destroying harmful organisms or substances that could possibly interfere with human health.

Major histocompatibility complex

is the “fingerprint” of proteins on the outside of cells that are identified as “self”. Normal cells of the body – “self”. Invading or infected cells – “non-self”.

Macrophages

Phagocytic cells that move out of capillaries and digest foreign materials.

Lymphocytes

Non-phagocytic cells which manufacture antibodies that fight infection.

Antibodies

Chemicals that kill bacteria or stop them from reproducing. Can be man made or found in nature.

Respiratory system

The Primary site of gas exchange for the human body. It is on the inside of the body for protection and to stay moist. It has a large surface area for bulk exchange of gasses.

Nasal Cavity

Air comes in from the nose and is modified (cooled, warmed, moistened) before moving on to more sensitive areas. Hairs and mucus also trap foreign particles.

Pharynx

(throat) Houses openings for respiratory and digestive systems. Also contains vocal cords.

Epiglottis

A flap of tissue that moves over when swallowing and covers over the opening to the lungs and vocal cords.

Trachea

Tube that goes down to the lungs. Has cartilage rings in the walls.

Bronchi

Trachea branches into two smaller tubes, one per lung.

Bronchioles

Tubes get smaller and more numerous, like the branches of a tree.

Alveoli

Elastic cluster of sacs that is the actual site of gas exchange. Thin walls and high vascularization.

Diaphragm

The sheet of muscle that lies inferior to the lungs. Moves down to force air into the lungs.

Intercostal muscles

which sit between and are attached to the ribs.

Inhalation

Active phase of breathing. External intercostal muscles and diaphragm contract. Rib cage expands, diaphragm moves down. Chest cavity increases in volume, which decreases air pressure inside the lungs and air rushes in.

Exhalation

Passive phase of breathing. Diaphragm and external intercostals relax. Internal intercostals contract, pulling the rib cage back to its original position. Chest cavity becomes smaller, increasing the air pressure inside the lung. Air moves out of the lung.

Tidal volume

The volume of air inhaled and exhaled in a normal breathing movement. Approx 500ml.

Inspiratory reserve volume

The additional volume of air that can be taken in beyond the regular tidal volume. Avg

Expiratory reserve volume

The additional volume of air that can be forced out of the lungs beyond regular tidal volume. Avg

Vital capacity

The Total volume of air that can be moved into and out of the lungs.

Residual volume

The volume of air that cannot be forced out since the lungs never collapse under normal circumstances.