Chapter 42 (circulation and gas exchange)

Circulatory system

The circulatory system is the body’s way of moving blood around. It carries oxygen and nutrients to your cells and takes away waste.

Gastrovascular cavity

simple body space that helps some animals both digest food and circulate nutrients. It’s basically one hollow cavity that does two jobs instead of having a separate stomach and circulatory system.

Open circulatory system

blood doesn’t stay inside vessels all the time. Instead, it flows freely around the organs before returning to the heart. This is common in insects and many other invertebrates.

closed circulatory system 

blood stays inside blood vessels as it moves through the body. This system is found in humans and many other animals and allows blood to flow quickly and efficiently.

Systole 

contraction, heart pumps blood

Diastole

relaxation, heart fills with blood

cardiac output

volume of blood the left ventricle pumps per minute

heart murmur

problem in which blood squirts back through a defective valve; mild to severe

Three levels of vessels 

Outer

connective tissue with elastic fibers (thicker in arteries)

Middle

smooth muscle with elastic fibers (thicker in arteries)

Inner

made of single layer of flat cells 

blood pressure

hydrostatic pressure that blood exerts against the walls of the vessels to propel blood

plasma

liquid part of blood. It carries nutrients, hormones, and waste products, and it helps move blood cells throughout the body.

serum

plasma without clotting factor

pluripotent stem cells 

special cells that can turn into almost any type of cell in the body. They are very flexible and can become nerve cells, muscle cells, blood cells, and many others, but they cannot form a whole organism on their own.

erythropoietin

hormone that stimulates the production of RBC’s

atherosclerosis

hardening or narrowing of the arteries due to build up of plaque

plaque

materials that enter arteries from bloodstream

hypertension 

high blood pressure 

gas exchange

process where oxygen is taken into the body and carbon dioxide is removed

Diaphragm

sheet of skeletal muscle that increases lung volume when contracted