The Human Body - Circulatory System Flashcards
The circulatory system is entirely closed, with capillaries connecting ___
Arterioles and venules
Two circuits in the circulatory system
- Systemic circulation in the body
- Pulmonary circulation in the lungs
Function of the systemic circulation
Circuit in the body that carries oxygen-rich blood from the left ventricle through the body and back to the right atrium. Blood passes through the tissues and organs, giving up oxygen and absorbing cellular wastes and carbon dioxide
Function of the pulmonary circulation
Circuit in the lungs that carries oxygen-poor blood from the right ventricle through the lungs and back to the left atrium. Blood passes through the lungs and is refreshed with oxygen and gives up carbon dioxide
Many cellular wastes are eliminated in passages through the ___
Liver and kidneys
Size of the heart
About the size of a clenched fist
The heart is made from ___
Cardiac muscle (myocardium)
The heart works as ___
Two paired pumps
The ___ side of the heart is more muscular
Left
Divides the heart down the middle into right and left sides
Septum
Each side of the heart is divided into ___
An upper chamber (atrium) and a lower chamber (ventricle)
The left side of the heart pumps blood to the ___
Body
The ___ side of the heart is a high-pressure pump
Left
The right side of the heart supplies blood to the ___
Lungs
The ___ side of the heart is a low-pressure pump
Right
The heart muscle is under the control of the ___
Autonomic nervous system
The heart has it’s own ___ and will ___ without its central nervous system control
- Electrical system
- Continue to function
The heart requires ___ and cannot function on ___ metabolism
- A continuous supply of oxygen and nutrients
- Anaerobic
The heart can tolerate a serious interruption of its own blood supply for only a few seconds before the signs of a ___ develop
Heart attack
The heart muscle’s blood supply comes from the ___
Aorta
The aorta has two branches at its base that form the ___
Left and right coronary arteries
These arteries supply the heart muscle with oxygenated blood
Left and right coronary arteries
The right side of the heart receives blood from ___
The veins of the body
The blood from the body into the heart enters from the ___
Superior and inferior venae cavae into the right atrium and then passes through the tricuspid valve to fill the right ventricle
After the right ventricle is filled, the ___ closes to prevent ___
- Tricuspid valve
- Backflow as the right ventricular contracts
Contraction of the right ventricle causes blood to ___
Flow through the pulmonic valve into the pulmonary artery and the pulmonary circulation
The left side of the heart receives oxygenated blood from ___
The lungs through the pulmonary veins into the left atrium
From the left atrium blood passes through the ___
Mitral valve into the left ventricle
Most muscular pumping chamber of the heart
Left ventricle
From the left ventricle blood passes through the ___
Aortic valve into the aorta and then to the arteries of the body
The flow of blood through the four heart chambers is governed by ___
One way valves
The chord tendineae are ___
Thin bands of fibrous tissue that attached to the valves in the heart and prevent them from inverting
When a valve controlling the filling of a heart chamber is open, the other valve allowing it to empty is ___
Shut
Normal adult resting heartbeat
60 to 100 bpm
HR
Heart rate
A well-conditioned athlete may have a normal resting heart rate of ___
45 to 60 bpm
During vigorous physical activity, the heart rate may rise to as fast as ___
180 bpm
At each beat, ___ of blood is ejected from the adult heart
70 to 80 mL
SV
Stroke volume
Stroke volume
The amount of blood moved in one beat
In one minute, the entire blood volume of ___ is circulated through all the vessels
5 to 6 L
Cardiac output
The amount of blood moved in one minute
CO
Cardiac output
Cardiac output calculation
CO = HR x SV
A network of specialized tissue with the capacity to conduct ___ runs through the heart
Electrical current
The flow of electrical current through this network in the heart causes ___
Smooth, coordinated contractions of the heart
These contractions of the heart produce ___
The pumping action of the heart
Each mechanical contraction of the heart is associated with ___
Two electrical processes
Two electrical processes that produce mechanical contraction of the heart
- Depolarization
- Repolarization
The electrical charges on the surface of the muscle cell change from positive to negative
Depolorization
The heart returns to its resting state and the positive charge is restored to the surface
Repolarization
Electrical impulse flow through the heart
- Begins high in the atria at the sinoatrial node
- Travels to the atrioventricular node and bundle of His
- Moves through the Purkinje fibers to the ventricles
The electrical impulse flow through the heart produces a smooth flow of electricity through the heart, which ___
Depolarizes the muscle and produces the coordinated pumping contraction
If areas of the heart’s conduction system are deprived of blood flow and oxygen, ___ can occur
Serious abnormalities of the heart’s rate, rhythm, and coordinated contraction leading to dangerously low blood pressure can occur
Carry blood from the heart to all body tissues
Arteries
Arteries branch into ___
Smaller arteries and then into arterioles
The arterioles branch into ___
The vast network of capillaries
The walls of an artery are made of ___
Fine, circular muscle tissue or fine circular muscle and elastic tissue
Arteries contract to ___
Accommodate loss of blood volume and increase blood pressure
Blood is supplied to tissues as they ___
Need it
The ability to respond to the needs of the body is possible because of the way arteries are ___
Constructed
The tunica media is ___
The middle layer of the artery formed from smooth muscles that can contract and dilate to change the diameter of the blood vessel
The aorta leaves the ___
Back left side of the heart
Location of the aorta
Just in front of the spine in the chest and abdominal cavities
Coronary arteries supply ___
The heart
Carotid arteries supply ___
The head
Hepatic arteries supply ___
The liver
Renal arteries supply ___
The kidneys
Mesenteric arteries supply ___
The digestive system
The aorta divides at the level of the ___ into the ___
- Umbilicus
- Two common iliac arteries that lead to the lower extremities
The pulmonary artery begins at ___
The right side of the heart and carries oxygen-depleted blood to the lungs
The pulse is most easily palpated at ___
The neck, wrist, or groin
The pulse is created by the ___
Forceful pumping of blood out of the left ventricle into the major arteries
A pulse can be felt most easily where ___
The larger arteries near the skin can be pushed against a solid structure, such as a bone or a large muscle
Central pulses
- Carotid artery
- Femoral artery
Peripheral pulses
- Radial artery
- Brachial artery
- Posterior tibial artery
- Dorsalis pedis artery
Less commonly used pulses
- Superficial temporal
- External maxillary
- Ulnar
Location of carotid artery pulse
Upper portion of the neck
Location of femoral artery pulse
In the groin
Location of radial artery pulse
At the wrist at the base of the thumb
Location of brachial artery pulse
On the medial aspect of the arm, midway between the elbow and shoulder
Location of posterior tibial artery pulse
Posterior to the medial malleolus
Location of the dorsals pedis artery pulse
On the top of the foot
How many capillary vessels in the body?
Billions
Blood in arteries is bright red because ___
The hemoglobin is rich in oxygen
Capillaries connect directly at one end with ___ and at the other end with the ___
- The flow-regulating arterioles
- Venules
Capillaries allow blood to move through them a ___
Single cell at a time
Once oxygen-depleted blood passes through the network of capillaries, it moves to the ___
Venules
Smallest branches of the veins
Venules
Blood returns to the heart via a ___
Network of larger and larger veins
Veins compared to arteries
Much thinner walls and are generally larger in diameter
The veins become larger and larger and ultimately form ___
Two major vessels called the superior and inferior venae cavae
Superior and inferior venae cavae location
Lie just to the right of the spine
Function of the superior and inferior venae cavae
Collect blood just before it enters the heart
Pressure generated by the heart dissipates as blood ___
Passes through the capillaries
Venous blood flow is assisted by ___
Gravity, skeletal muscle contraction, and intrathoracic pressure changes from breathing
One way flow in the veins is governed by ___
Valves within the veins
The superior and inferior venae cavae join at the ___
Right atrium of the heart
The right ventricle receives blood from ___
The right atrium and pumps it through the pulmonary arteries into the lungs
Great vessels
Venae cavae, aorta, and pulmonary arteries and veins
SVR is the resistance to blood flow within all blood vessels except the ___
Pulmonary vessels
SVR
Systemic vascular resistance
Blood is composed of ___
- Plasma
- Red blood cells
- White blood cells
- Platelets
- Protein molecules
Most carbon dioxide is carried in the form of ___
Bicarbonate dissolved in the plasma, while a tiny amount is carried by hemoglobin
The liquid portion of the blood
Plasma
Composition of plasma
- 92% water
- 7% proteins
- Very little oxygen (most is bound to the hemoglobin in red blood cells)
- Carbon dioxide as bicarbonate
- Nitrogen dissolved within the plasma
- Nutrients
- Cellular wastes
- Hormones & other cellular products
About ___ of plasma is water and proteins
99%
Majority of the proteins in plasma
Albumin
Albumin function in plasma
Controlling the movement of water into and out of the circulation
Purpose of nutrients carried by albumin
Fuel for the cells
Cellular wastes carried by plasma
Lactic acid, carbon dioxide, etc.
Solid organ located under the rib cage in the left upper quadrant of the abdomen
The spleen
Purpose of the spleen in the circulatory system
Although part of the lymphatic system, digests filtered degraded red blood cells and recycles the hemoglobin
Life span of red blood cell
About 120 days
Why is the spleen one of the most frequently injured abdominal organs after blunt trauma
Its tissue is delicate and it is directly under flexible ribs with very little soft tissue to cushion it
An injured spleen can produce significant internal bleeding because it is ___
So highly vascular
BP is expressed in ___
mm Hg
Average adult volume of blood
6 L
Average child volume of blood
2 to 3 L
Average infant volume of blood
300 mL
In all healthy people, the circulatory system is automatically adjusted and readjusted constantly so that ___ of the capacity of the arteries, veins, and capillaries holds ___ of the blood at that moment
- 100%
- 100%
The size of the arteries and veins is controlled by the ___
Nervous system
When perfusion is adequate, the cells’ ___ are met
Metabolic needs
Loss of normal blood pressure is an indication that ___
Blood is no longer circulating efficiently to every organ in the body
When ___ are affected the terms shock and hypoperfusion may be used interchangeably
Multiple systems
Shock vs hypoperfusion
Shock is always systemic, but hypoperfusion may be limited to a specific region of the body
Important cardiovascular values
- Systolic blood pressure
- Diastolic blood pressure
- Pulse pressure
- Preload
- Afterload
- Stroke volume
- Cardiac output
- Systemic vascular resistance
Amount of blood returning to the heart
Preload
Pressure to be overcome when left ventricle contracts (pressure within the aorta)
Afterload
___ is the same as after load
Diastolic pressure
Difference between systolic blood pressure and diastolic blood pressure
Pulse pressure
Too little preload and ___
Blood pressure falls
Too high preload and ___
The heart cannot move blood effectively
How does the arteries, veins, and heart adjust to a reduced blood volume and how quickly?
- The vessels constrict to provide a smaller bed for the reduced volume of blood to fill, and the heart pumps more rapidly to circulate the remaining blood more efficiently
- Within minutes
During blood loss the heart rate will increase to keep a cardiac output constant at ___
5 to 6 L/min
Measure of perfusion that can detect shock
Mean Arterial Pressure (MAP)
Indicates the average arterial pressure during systole and diastole
Mean arterial pressure (MAP)
MAP equation
MAP = (HR x SV) x SVR
MAP = CO x SVR
___ of blood is found within the heart, arteries, and capillaries
About 30%
___ of blood is found within the veins and venules
About 70%
Nutrients move from the capillaries into ___
The interstitial space and into the intracellular space
Two main forces at work inside the capillary
- Hydrostatic pressure
- Oncotic pressure
___ occurs as fluid pushes against the vessel walls to force fluid out of the capillary
Hydrostatic pressure
___ is the opposing force to hydrostatic pressure and occurs because proteins in the blood plasma cause water to be pulled into the capillary by diffusion
Oncotic pressure
Coagulation occurs as the result of a complex chemical process that creates ___
Small fibers near the injured blood vessel, trapping red blood cells
Clotting after venous or capillary bleeding normally takes ___
6 to 10 minutes
Purpose of white blood cells
Fights infection
Purpose of red blood cells
Transports oxygen
Purpose of Plasma
Transports carbon dioxide
Purpose of chemicals within the plasma
Controls (buffers) pH
Purpose of plasma (water)
Transports wastes and nutrients
Purpose of platelets and clotting factors in the plasma
Clotting