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Biology Chapter 23: Circulation System

Terms in this set (50)

Why is a circulatory system needed in most multicellular organisms?
their body is too large and too complex for exchange to occur by diffusion alone
arteries (blood flow)
carry blood away from the heart to body organs and tissues
veins (blood flow)
carry blood returning to the heart
capillaries (blood flow)
carry blood between arteries and veins within each tissue
What is the vertebrate circulatory system often called?
cardiovascular system
cardiovascular system
closed circulatory system with a heart and a branching network of arteries, capillaries, and veins
single circulation system
a single pump and circuit, in fish: Heart → Gills → Body → Heart
double circulation system
separate pulmonary and systemic circuits, in which blood passes through the heart after completing each circuit
Do humans have a single or double circulation system?
double circulation system
What are the two circuits of the double circulation system?
pulmonary circuit and systemic circuit
pulmonary circuit
carries blood between the heart and gas exchange tissues in the lungs: Heart → Lungs → Heart
systemic circuit
carries blood between the heart and the rest of the body: Heart → Body → Heart
How many chambers does the heart have in birds and mammals?
four
How many atria and ventricles are there?
two each
What kind of blood does the right side of the heart handle?
oxygen-poor
What kind of blood does the left side of the heart handle?
oxygen-rich
In the pulmonary circuit, the pulmonary arteries carry what kind of blood to the lungs?
oxygen-poor
In the pulmonary circuit, how does blood flow back into the heart?
through the pulmonary veins
In the pulmonary circuit, the pulmonary veins carry what kind of blood to the heart from the lungs?
oxygen-rich
In the systemic circuit, what kind of blood exits the heart ?
oxygen-rich
In the systemic circuit, how does blood exit the heart?
aorta
In the systemic circuit, after journeying to the body tissues, what returns blood from the body to the heart?
superior vena cava and inferior vena cava
Where do ventricles pump blood to?
into arteries
Why are the ventricles thicker and more muscular than the atriums?
in order to overcome resistance to flow and to move blood a greater distance
What is the job of the valves in the heart?
keep blood flowing in one direction through the heart, keeping blood from moving backwards
Where are the atrioventricular (AV) valves located?
between the atria and ventricles on both the right and left side of the heart
Where are the semilunar valves located?
the exit from each ventricle
What is the SA (sinoatrial) node?
pacemaker of the heart
Where is the SA (sinoatrial) node located?
in the upper wall of the right atrium
What does the SA (sinoatrial) node do?
generate electrical impulses in atria and
set the rate of heart contractions
coronary arteries
branch from the aorta in order to feed the heart muscle oxygen and nutrients
What happens when a person has a heart attack?
damage or death of cardiac muscle tissue and
usually results from a blocked coronary artery
cardiovascular disease
disorders of the heart and blood vessels
What develops in the inner walls of arteries during atherosclerosis?
plaques, narrowing the passages through which blood can flow
atherosclerosis
arteries of most victims of heart attack became impaired gradually by a chronic cardiovascular disease
angioplasty
a treatment for atherosclerosis which, expands a narrowed artery by inserting a mesh tube called a stent
What are general characteristics of arteries?
the thickest walls with elastic fibers that recoil after stretching and contain a thick layer of smooth muscle in their walls that can constrict and reduce blood flow
What are general characteristics of capillaries?
have only a single layer of epithelial cells wrapped in an extracellular matrix
What is the main function of capillaries?
to exchange gas (O₂ and CO₂), nutrients and waste with body cells
What are general characteristics of veins?
have thinner walls, lower blood pressure, velocity and one-way valves permit blood to flow only toward the heart
blood pressure
the force that blood exerts against the walls of blood vessels
How is blood pressure created?
the pumping of the heart which drives the flow of blood
Where is blood pressure the highest?
arteries
How is blood pressure measured?
systolic/diastolic
What causes a pulse?
contraction of the ventricles cause blood to stretch the elastic walls of the arteries
hypertension
a serious cardiovascular problem in which the blood pressure remains higher than the normal range
What is prolonged hypertension the major cause of?
heart failure, vascular disease, renal failure, and stroke
What are three ways that high blood pressure harms the cardiovascular system?
1. Requiring the heart to work harder to pump blood throughout the body.
2. Weakening of heart muscles
3. Left ventricle may enlarge
4. Increased force may cause tiny ruptures which promote plaque buildup.
What are things you can do to help prevent hypertension?
eating a heart-healthy diet, not smoking, avoiding excess alcohol, exercising regularly, and maintaining a healthy weight
What is considered normal blood pressure?
120/80 mm Hg
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