Cardiac Muscle Tissue
makes up the walls of the heart. Its contraction pumps blood and accounts for the heartbeat. It has branching, striated cells, each with a single nucleus, and is involuntary.
region that holds adjacent cardiac muscle cells together; disks appear as dense bands at right angles to the muscle striations
junction between cells in which the adjacent plasma membranes do not touch but are held together by intercellular filaments attached to button-like thickenings. (located where tissues get stretched) Ex: in organs such as heart, stomach and bladder
allows cells to communicate. Lends strength to the cells but it also allows small molecules and ions to pass between them. Important in heart muscle and smooth muscles because they permit a flow of ions that is required for the cells to contract as a unit
What is the function of the septum?
prevents oxygen poor blood from mixing with oxygen rich blood
return blood to the ♥ once it has passed through the capillary system. Blood flow the veins of arms/legs occurs against the force of gravity; walls=thicker then arteries; large veins contain valves to prevent the blood from reversing.
smallest blood vessels; are narrow (blood cells pass one at a time); one cell layer thick; allows change across the cell (brings nutrients and oxygen to the tissues; remove carbon dioxide and other wastes).
large blood vessels that carry blood from the ♥ to the tissues of the body. They have thick walls and can withstand the pressure the ♥ exerts as it contracts
carries blood between ♥ and lungs
carries blood between ♥ and rest of body
Compare the walls of the atria and the ventricles
Atria have thin walls whereas ventricles have thick, muscular walls.
Sinoatrial Node (SA Node)
initiates the ♥ beat every .85 seconds
Atrioventricular Node (AV Node)
keeps the ♥beat regular-called the pacemaker; sends signals to the ventricles to contract through the Purkinje fibers
the force of blood on artery walls
the force felt in the arteries when the ventricles contract
the force felt in the arteries when the ventricles relax
Pathway of air into the lungs
Pharynx→ Larynx→ Trachea→ Bronchi→ Lungs
tiny air sacs; are composed of squamous epithelial cells, surrounded by elastic fibers
How is air forced in/out of the lungs?
Air is forced into the lungs by a large muscle called the diaphragm.
What filters and warms the air?
Prior to entering the lungs, air is warmed, moistened, and filtered in the nose and mouth. Hair, cilia and mucus contribute
What happens when oxygen diffuses into the blood?
When oxygen enters the blood it combines with hemoglobin, which is found in R blood cells.
In what form is carbon dioxide transported in the blood? Where is it carried?
In the form of bicarbonate ion (HCo3-) and is carried in blood plasma.
small arteries that affect blood pressure
Vertebrates have what kind of circulatory system?
muscle tissue the heart is composed of
Upper chambers of the heart
receive blood; atria (atrium is singular)
Lower chambers of the heart
pump blood out of the heart; ventricles
What is the function of the R ventricle?
sends blood to the lungs
What is the function of the L ventricle?
sends blood throughout the body
Which ventricle has thicker walls?
Where are the muscle fibers that initiate heartbeat located?
the exchange of oxygen and carbon dioxide between the air, blood, and tissues
What do the bronchi divide into?
How many alveoli are there per human lung?
What happens to oxygen after it reaches the air sacs?
oxygen diffuses across the alveoli into the blood
Pathway of blood: oxygen poor
enters the R atrium from the superior and inferior vena cava
blood goes through the tricuspid valve and enters R ventricle
moves through pulmonary semilunar valve into L and R pulmonary arteries
Pathway of blood: oxygen rich
pulmonary veins bring oxygenated blood from lungs
enters L atrium through bicuspid valve (mitral)
enters L ventricle, through aortic valve into aorta
aorta transports blood to body