Chapter 11 - Cardiovadcular System Flashcards
What are the three types of blood vessels in the body?
Arteries, veins and capillaries
What are the arteries?
A large blood vessels that carry blood AWAY from heart
Their walls are lined with connective tissue, muscle tissue and elastic fibres, with an innermost layer of epithelial cells called endothelium
What do endothelial cells do?
Found in all blood vessels. They secrete factors that affect size of blood vessels, reduce blood clotting, and promote the growth of blood vessels.
They must be strong enough to withstand High pressures of pumping action from heart. Their elastic walls allow them to expand as the heartbeat forces blood into arterial system throughout body
What are arterioles?
Smaller branches of arteries. Thinner than arteries and carry blood to tiniest of blood vessels, the capillaries
What do the capillaries do?
Carry oxygenated blood from arteries and arterioles to the body cells
Where does the nutrients from the blood in the capillaries go?
The capillaries thin walls allow the oxygen and nutrients out of the bloodstream and into the cells. There, nutrients are burned in presence of oxygen (catabolism) to release energy
While the nutrients are burning, what is happening at the same time with the waste products?
Waste products (H2O and CO2) pass out of the cells and into the thin-walled capillaries. The waste-filled blood then flows back to the hear in small venules, which combine to make larger vessels called veins
What are veins?
Thinner walls than arteries. They conduct blood that’s given up most of its oxygen toward the heart from the tissues
Veins compared to arteries
Veins: little elastic tissue and less connective tissue than arteries. Blood pressure in veins is extremely low compared to pressure in arteries.
How does the blood keep moving back toward the heart in the veins?
They have valves that prevent backflow of blood and to keep the blood moving in one direction. Muscular action also helps movement if blood in veins
Oxygen poor blood enters right side of heart and then travels to pulmonary artery. Where do the two branches of the pulmonary artery lead to?
One branch leads to the left lung, the other to the right lung
What do the branches of the pulmonary artery do?
Continue to divide and subdivide within the lungs, forming smaller and smaller vessels (arterioles) and then reaching the lung capillaries.
Pulmonary artery is only artery in body that carries oxygen deficient blood
While passing through lung (pulmonary) capillaries, blood absorbs the oxygen that entered body through inhalation. Where does the newly oxygenated blood go?
It returns immediately to the heart through pulmonary veins.
Pulmonary veins are only veins that carry oxygenated blood
What is pulmonary circulation?
Circulation of blood through vessels from the heart to the lungs and then back to the heart again
Oxygenated blood enters left side of heart from pulmonary veins. What happens next?
Left side of heart pumps blood out of heart through the aorta
What is the single largest artery in the body?
The aorta
Aorta moves up at first (ascending aorta) then arches over doesally and runs downward (descending aorta) right in front of the vertebral column. What does it do then?
Aorta divides into numerous branches called arteries that carry oxygenated blood to all body parts
What are some arterial branches?
Brachial, axillary, splenic, gastric, and renal arteries
What do the carotid arteries do?
Supply blood to the head and the neck
What do the arterial vessels, and what happens afterwards?
They branch further to form smaller arterioles, still carrying oxygenated blood. The arterioles then branch into smaller tissue capillaries, near the body cells.
Where does the oxygen leave the blood and where does it go?
It leaves in the tissue capillaries through the thin walls of the capillaries. This is where food is broken down, in the presence of oxygen, and energy is released (catabolism)
What happens to the blood as oxygen leaves?
CO2 then leaves cells and enters into tissue capillaries. So the blood returning to the heart from tissue capillaries through the venules and veins is oxygen deficient and CO2 filled.
Where does the oxygen poor blood enter the heart from?
The venae cavae
What is systemic circulation?
Pathway of blood from heart to tissue capillaries and back to the heart
Where does the heart lie?
In the thoracic cavity, just behind the breastbone in the mediastinum (between the lungs)
How many chambers does the heart have?
- 2 upper chambers called atria. 2 lower chambers called ventricles
Blood enters venae cavae (2 largest veins). What does the Superior Vena Cava and the Inferior Vena Cava do?
SVC: drains blood from upper portion of body
IVC: carries blood from lower part of body
Where do the venae cavae bring the oxygen-poor blood, and what happens when it’s there?
It goes to the atrium (thin walled in upper right chamber). The right atrium contracts to force blood through the tricuspid valve into the right ventricle (lower right chamber).
What does the tricuspid valve do?
It’s a one way passage for blood to flow. It prevents backflow into the right atrium.
During what does the tricuspid valve stay shut?
When the right ventricle contracts oxygen poor blood through the pulmonary valve, and into the pulmonary artery
What does the pulmonary artery do with oxygen poor blood?
It branches out and carries it to each lung
What happens to the blood once it enters the lung capillaries?
It loses its CO2 into lung tissue and oxygen enters and is brought back to the heart in the pulmonary veins, newly oxygenated blood.
Where does the oxygenated blood enter? What happens then?
Enters the left atrium from the pulmonary veins.
Walls of left atrium contract to force blood though the mitral valve (bicuspid) and into the left ventricle
What does the left ventricle do?
Propels blood through the aortic valve and into the aorta, which branches to carry blood all over body (aortic valve closes to prevent return of aortic blood)
What are the four chambers of the heart separated by?
Separated by partitions called Septa (singular: septum)