Chapter 10- Circulatory System Flashcards
What do open circulatory systems not have
What do closed-circulatory systems have
Open systems have no vessels
Closed systems have vessels and a pump
What do circulatory systems do for the cells
Are they open or closed systems
Circulatory systems ensure that cells get the nutrients and oxygen that it needs
Can be open or closed
What are the functions of the circulatory system
Transport, distribute heat, house immune system cells
What does the circulatory system transport
Gases, nutrients, wastes, chemical messengers (example: hormones)
What does the circulatory system consist of
Blood, the heart, arteries, arterioles, capillaries, venules, veins
What do the arteries and arterioles do
What do the veins and venules do
Carry blood away from the heart
Carry blood toward the heart
What causes you to feel a pulse
Blood entering the arteries each time your heart contracts
What are arteries
Large blood vessels that carry blood away from the heart
Are elastic and can stretch
Under a lot of pressure
How many layers do arteries consist of
What is each layer made out of
Three layers
Outer and inner layer made of connective tissue
Middle layer is made of smooth muscle fibers and elastic connective tissue
What are arterioles
Smaller, elastic arteries
What are the diameter of arteries and arterioles regulated by
How
The automatic nervous system
Nerve impulses cause the smooth muscle that lines the wall of the artery and arterioles to contract
What is vasoconstriction
Does it increase or decrease blood flow
When the arteries smooth muscle contracts to reduce its diameter, Reducing blood flow to the area
What is vasodilation
Does it increase or decrease blood flow
When the smooth muscle of the artery relaxes to increase its diameter
This increases blood flow to an area
What is atherosclerosis Caused by
What is the result
Caused by the accumulation of plaque and fat deposits in the artery
As a result, the diameter of the arteries narrows, making it more difficult for blood to pass through
What is the cause of a heart attack
What happens to cardiac muscles during heart attack
Caused by the accumulation of plaque and fat deposits or a clots, which blocks an artery in the heart
The heart cells are starved of oxygen, so cardiac muscle cells die
What is an aneurysm caused by? Where are the most common sites that this happens? What is the effect of an aneurysm
Caused by birth defects, injury, genetics
Common sites include aorta, abdominal aorta, and arteries in the brain
The effect is that the weekend artery or vein begins to protrude as blood surges through
What is the cause of a stroke? What is a stroke in the brain called?
Caused by a bulge in the arteries/vein bursting
Hemorrhagic stroke
What do precapillary sphincter muscles control
The movement of blood from the arterioles to the capillaries
What are capillaries composed of
Site of ____ and ____
Composed of a single layer of cells
Site of fluid and gas exchange
What do red blood cells do inside the capillaries
What happens to this next?
Releases their oxygen
Oxygen passes through the capillary wall into the interstitial space
What is interstitial space
The space that is found between the capillary and the cell
Surrounds the cell
When does bruising occur
When capillaries are damaged and blood flows into the interstitial space
What are venules Composed of
What are they lined with and what do they do for the heart
Capillaries merge into larger venules
Lined with smooth muscles
Carry deoxygenated blood towards the heart
What do veins do
When does the diameter increase
What happens when the diameter increases
Carry deoxygenated blood
Increase as they approach the heart
Fluid pressure is reduced in veins
How does skeletal muscle contraction aid bloodflow toward the heart
Muscles Bulge when they contract reduces the diameter of the vein
pressure inside the vein increases valves to push open
blood flows back to the heart
What do one-way valves do
Prevent blood from flowing backwards and steers blood towards the heart
When are vericose veins made
What are the causes
Created when valves do not close properly, which causes blood to pool in the veins
Heredity, standing for long periods or compression of veins
How are things used as blood reservoirs
When you’re stressed, venous flow increases to help meet energy demands
Nervous impulses contract the smooth muscle in veins
This raises blood pressure
Therefore more blood reaches the heart
Where is the heart located
How big is it
What is it surrounded by
Thoracic cavity
Size of your fist
Surrounded by a fluid filled membrane called the pericardium which prevents friction
What protects and cushions the heart
What does the coronary artery supply the heart with
Fat
Blood
How many chambers does the heart have and what are they
What is the septum
Four chambers: left and right atria, left and right ventricles
Septum is a wall of muscle that separates the right and left sides of the heart
What do the atria do
What type of blood enters the left atrium and what type of blood enters the right atrium
Atria act like holding chambers for blood entering the hearts
Blood from pulmonary system enters left
Blood from systemic system enters the right
What are ventricles
Strong muscular chambers that pump blood away from the heart
What is pulmonary circulation
What is systemic circulation
Blood vessels that carry blood to and from the lungs
Blood vessels that carry blood to and from the body
What are the two largest veins
Superior vena cava and inferior vena cava
What do the superior and inferior vena cava do
Superior: carries deoxygenated blood from your head to your heart
Inferior: carries deoxygenated blood from your body to your heart
Explain bloodflow
Deoxygenated blood reaches the heart through inferior and superior vena cava and empties into the right atrium
Blood moves through AV valve into the right ventricle
Blood pumped through semi lunar valves into left and right pulmonary arteries
In lungs, oxygen diffuses into the blood
Oxygenated blood enters pulmonary veins and goes back to the heart
Blood enters left atrium, moves through AV valve, into left ventricle
Blood pumped through semi lunar valves into the aorta, where travels to body tissues
How do tissues use blood
What happens to the blood after the tissues have used it
Use the oxygen, nutrients, and fluids that are in blood
Then, the deoxygenated blood moves through the vein system into the inferior and superior vena cava
What do the coronary arteries supply the heart muscle cells with
What is angina. How can it be caused and fixed?
Oxygen and nutrients
Chest pain that occurs when too little oxygen reaches the heart
Can be caused by a blockage, which can be bypassed by using veins from other parts of the body… These are grafted into the heart
What is cardiac catheterization
A technique used to detect coronary artery blockage
What is myogenic muscle
What is an example of this in our bodies
Muscles that can contract without external nerve stimulation
Cardiac muscle tissue
What is the hearts tempo set by
What is this and what does it act as
The sinoatrial node
This is a bundle of specialized nerves and muscle located in the upper right atrium, it acts as a pacemaker and sets a rhythm of about 70 bpm
Where is the contraction of the heart generated
How does this contraction work
The SA node
Electrical impulses pass on to both atria, causing them to simultaneously contract, the impulses then move to the AV node. The message is then relayed quickly down to special nerves in the septum called the bundle of his. It is concept down to the Purkinje fibers. The result is both ventricles are now stimulated to contract at the same time
What do baroreceptors do
Detect blood pressure in the aorta and carotid artery
Then, these receptors signal the medulla oblongata, which responds by stimulating the autonomic nervous system
What does the autonomic nervous system consists of, what does it do and what can its nerve impulses affect
Consists of parasympathetic and sympathetic nervous system
Regulates equilibrium
Nerve impulses can affect heart rate
What does the parasympathetic nervous system do
What does the sympathetic nervous system do
Tells heart to beat at a normal rate
Tells heart to increase heart rate
How do sympathetic nerves work
Sympathetic nerve send impulses to the pacemaker to increased heart rate, which increases blood flow to the tissues
What is tachychardia
What is bradycardia
Heart rate exceeds 100bpm
Low heart rate
How do parasympathetic nerves work
Parasympathetic nerves are stimulated, nerve impulse is sent to the pacemaker to slow the heart down
What does an electrocardiogram do
Measure the electrical activity of the heart
What is the lubb dubb sound of the heart we hear caused by
Opening and closing of heart valves
Lubb: Closing of AV valves (ventricles pumping)
Dubb: Closing of semi lunar valves (atria pumping)
What is systole
What is diastole
Period of contraction
Period Of relaxation
Describe the cycle of contraction and relaxation
Atria are relaxed and filled with blood
Atria contract and AV valves open
Blood flows and fills the ventricles
Ventricles contract and the pressure causes the AV valves to close
Blood pushes through the semi lunar valves and into the arteries
Semi lunar valves close
Ventricular relaxation
When does heart murmur occur
When blood leaks past a closed heart valve
What are two ways the heart makes up for decreased oxygen
The heart can beat faster or the cardiac muscle can stretch more than normal
What are beta blockers used for
They slow heart rate down. Often used to treat irregular heartbeats and high blood pressure
How do beta blockers work
Epinephrine, a stress hormone, binds to receptors on heart cells and blood vessels
This increases heart rate and narrows blood vessels
Beta blockers work by binding to the receptor site on the cell so epinephrine can’t bind
What is cardiac output
How do you calculate it
The amount of blood that flows from the heart each minute
Cardiac output = heart rate x stroke volume
What kind of heart rate do people with well-developed hearts have
How do weaker hearts compensate
Low heart rate because they can pump greater volumes of blood
By increasing the heart rate
How many factors affect cardiac output and what are they
Two factors: heart rate and stroke volume
What is heart rate
What is stroke volume
Heart beats per minute
Amount of blood in mL that is pumped with each beat
What is blood-pressure and how is it measured
Pressure exerted on the walls of the arteries
Sphygmomanometer
Where is blood-pressure highest, high, and where is it low and lowest
Highest: left ventricle
High: systemic circulation
Low: pulmonary circulation
Lowest: right side of heart
How many factors affect blood pressure and what are they
Five factors
Cardiac output, hormones, nervous stimulation, metabolic waste, arteriolar resistance
What is arteriolar resistance
As the smooth muscle in the arterials contract, the diameter decreases, so less blood enters
More blood is then left in the artery which increases the arteries blood pressure
How do hormones and nerve stimulation affect blood pressure
Both cause the construction of arteries and arterioles and increase blood pressure
What are metabolite wastes and what do they do
Compounds such as acids and carbon dioxide, which both cause vessels to dilate, which decreases blood pressure
What happens when blood pressure is too high… Too low
To high: vessels are damaged, if you add stress, vessels rupture
Too low: tissues will not receive enough blood
What is hypertension
What is caused by
Persistent high blood pressure
Caused by heredity and poor diet
How does high-pressure work
Parasympathetic nerve function increases while sympathetic function decreases
Arterioles dilate and bloodflow increases
Heart rate and cardiac output decreases, which means pressure decreases
How does low-pressure work
Sympathetic nerve function goes up while parasympathetic nerve function decreases
Arterioles constrict and bloodflow decreases
Are great and cardiac output increase, which means pressure increases
What are the functions of adrenalin
Releases red blood cells from the spleen
Vasodilation of arterials in heart, brain, muscle
Vasoconstriction of arterioles in kidneys, stomach, intestines
What is thermoregulation
The maintenance of body temperature within a range that enables cells to function
What happens to the body when it is hot
Thermo receptors in the skin detect a rise in temperature to the hypothalamus
The hypothalamus sends a nerve impulse to the sweat glands, and you begin to sweat
Evaporation of perspiration cools the skin
Nerve impulse also sent to blood vessels, causing them to dilate, increasing blood flow to skin
What happens to your body when it is cold
Chemoreceptors in skin send nerve impulse to hypothalamus
Hypothalamus send message to Smooth muscle in arterials to constrict, which produces heat loss
To smooth muscle around hair follicles to stand on and, trapping heat
To skeletal muscle to initiate shivering, which generates heat
What do capillaries do
Provide cells with nutrients and oxygen
Take away cell wastes
Maintain a constant fluid level
Where does filtration occur and what happens during filtration
Occurs in the arteriole end of the capillary
Water and small ions move out of the Cappellar he and into the Extracellular fluid
Movement is the result of pressure gradient from high to low pressure
Where does absorption occur and what happens during absorption
Occurs in the venule end of the capillary
Water moves from extracellular fluid into the capillary
Movement is the result of osmotic gradient from high to low concentration of water
What forces determine water movement between blood and extracellular fluid
Fluid pressure and osmotic pressure
What does the lymphatic system do
Return small amounts of protein that were leaked from the capillaries back to the circulatory system
What do lymph vessels use to move the fluids
One-way valves and muscular contractions
What is the main duct of the lymphatic system called
The thoracic duct
What do lymph nodes do
Manufacture and house macrophages and store lymphocytes
What do all blood cells in the body begin as
What produces all blood cells
Stem cells
Red bone marrow
Where is red bone marrow found in children? In adults?
Children: most bones
Adults: found in cranium, sternum, ribs, spinal column, and long bones
What is the spleen
One of the body’s largest lymphoid organs
When does the spleen release red blood cells
When there is low blood pressure or oxygen levels drop
What happens to the thymus gland with age
Where is it located
Get smaller with age
Located in front of trachea, above the heart
