14: Animal Blood Circulation Flashcards
Module 3, Lesson 3
In ____, the cell’s surface is a point of exchange with the environment.
Single-celled organisms
List three purposes of the circulatory system.
- Transportation
- Regulation
- Protection
The circulatory system delivers ____ to cells and removes ____.
Oxygen and nutrients ; metabolic waste
The circulatory system helps regulate homeostasis by transporting…
Regulatory hormones
The circulatory system helps protect the body from…
Mechanical wounds and invading pathogens
List the two major components of blood.
- Plasma
- Formed elements
____ is mostly water and circulates several kind of elements.
Plasma
List the three types of formed elements found in the blood.
- Erythrocytes
- Leukocytes
- Platelets
____ make up about 45% of total blood volume and contain hemoglobin.
Erythrocytes
(red blood cells)
____ make up less than 1% of total blood volume and play a role in the immune system.
Leukocytes
(white blood cells)
____ are cell fragments involved in blood clotting.
Platelets
True or false:
Formed elements must constantly be replaced.
True
Formed elements develop from pluripotent stem cells in the…
Bone marrow
____ is the process by which formed elements are produced in the bone marrow.
Hematopoiesis
When blood oxygen levels drop, the kidneys convert plasma into a hormone called…
Erythropoietin
Erythropoietin (EPO) is a hormone that increases blood’s oxygen carrying capacity by…
Increasing the production of erythrocytes
The process by which EPO stimulates the production of erythrocytes is called…
Erythropoiesis
When blood vessels are damaged, the vessel walls…
Constrict
____ congregate around a wounded blood vessel and stick to each to seal off the wounded area.
Platelets
When a blood vessel is damaged, platelets initiate a cascade of…
Enzymatic reactions
The enzymatic reactions triggered by platelets result in the production of ____, which helps platelets form a clot around the wound.
Fibrillin threads
(a protein)
If a blood clot dislodged from the wounded area too quickly, it could…
Block blood vessels
List the three main types of circulatory systems.
- No circulatory system
- Open circulatory system
- Closed circulatory system
Sponges lack a circulatory system, so they use ____ to circulate water.
Incurrent and excurrent pores
Hydras and nematodes have no circulatory systems, so they use ____ to circulate water and nutrients.
Their gastrointestinal cavities
In a(n) ____, there is no distinction between the circulating fluid and the extracellular fluid.
Open circulatory system
The circulating fluid in an open circulatory system is called…
Hemolymph
An open circulatory system lacks ____ to connect circulatory pathways with the heart.
Capillaries
True or false:
Hemolymph circulates faster in an open circulatory system than blood does in a closed system.
False
In a(n) ____, capillaries join circulatory pathways leading away from the heart.
Closed circulatory system
In a closed circulatory system, ____ and ____ may leak out of the capillaries.
Plasma and leukocytes
Plasma that has leaked out of the circulatory system is called…
Lymph
Lymph is collected by the ____, which empties back into a vein near the heart.
Lymphatic system
A fish heart has ____ chambers that pump blood.
Two
In a fish circulatory system, blood first travels to the ____, where it unloads carbon dioxide and receives oxygen.
Gills
In fish, the lack of a separate pulmonary circuit means blood pressure is ____ past the gills.
Lower
Amphibians have a ____-chambered heart.
Three
An amphibian heart has ____ atrium (atria) and ____ ventricle(s).
Two ; one
____ receive blood from the veins.
Atria
____ pump blood into the arteries.
Ventricles
In amphibians and other higher animals, blood pumped by the heart first travels through ____ to the lungs.
Pulmonary arteries
Once blood is oxygenated in the lungs, it returns to the heart via…
Pulmonary veins
____ occurs when an animal has both a pulmonary circulation system and a systemic circulation system.
Double circulation
The ____ circulatory system moves blood from the heart to the rest of the body.
Systemic
True or false:
In amphibians, there is a potential for oxygenated and deoxygenated blood to mix.
True
Oxygenated and deoxygenated blood can mix in amphibians’ ventricles because…
The separation of pulmonary and systemic blood is incomplete.
Reptiles have an incomplete ____-chambered heart.
Four
Most reptiles have an incomplete ____, which divides the ventricles.
Septum
Oxygenated and deoxygenated blood do not mix in reptiles and mammals because…
The septum divides the ventricles
Mammals have a ____-chambered heart.
Four
The ____ are large blood vessels that deliver deoxygenated blood to the right atrium.
Superior and inferior vena cava
List the path that blood takes through the mammalian heart.
- Right atrium
- Right ventricle
- Lungs
- Left atrium
- Left ventricle
Blood in the left ventricle is pumped into the body through the…
Aorta
How does the heart beat?
(four steps)
- Both atria fill with blood
- The atria contract simultaneously
- Blood is pumped into the ventricles
- The ventricles contract simultaneously
Having a double circulatory system greatly increases the ____ of the four-chambered heart.
Efficiency
Endotherms require highly efficient circulation in order to…
Support their high metabolic rates
Electrical pulses are conducted through specialized cardiac tissues that receive impulses from the…
Autonomic nervous system
Specialized ____ are able to produce and conduct cardiac impulses.
Cardiac tissues
List the steps in the cardiac cycle.
(five)
- An impulse is sent from the sinoatrial node
- The signal travels to surrounding atrial tissue, causing them to beat
- The beating of the atria stimulates the atrioventricular node
- Purkinje fibers contract to conduct the cardiac signal through the septum
- The signal reaches the ventricles, causing them to beat
The sinoatrial node is located in the…
Right atrium
The sinoatrial node is sometimes called a…
“pacemaker”
If the ____ is not functioning properly, the heart may beat too quickly or too slowly.
Sinoatrial node
If blood clots are blocking any arteries or blood vessels, heart rhythms may become dysfunctional, which is called…
Fibrillation
The human heart usually beats about ____ per second.
Once
(~75 bpm)
The force with which the ventricles contract is the main factor determining…
Blood pressure
Blood pressure can be measured using a…
Sphygmomanometer
How does a blood pressure cuff work?
(three steps)
- Cuff is inflated around the brachial artery, closing it
- Cuff is deflated until the pulse is heard
- Cuff is deflated until the sound disappears
The blood pressure when the ventricles contract is the…
Systolic pressure
(top number)
The blood pressure when the ventricles are relaxed is the…
Diastolic pressure
(bottom number)
____ occurs when the systolic and/or diastolic blood pressures are above the normal ranges.
Hypertension
(high blood pressure)
____ carry blood away from the heart.
Arteries
True or false:
Arteries always carry oxygenated blood.
False
All of them do except for the pulmonary artery.
Arteries branch into smaller blood vessels called…
Arterioles
Arterioles branch into smaller blood vessels called…
Capillaries
Oxygen, nutrients, and wastes are exchanged with tissues in the…
Capillaries
____ carry blood towards the heart.
Veins
True or false:
Veins always carry deoxygenated blood.
False
All veins do except for the pulmonary vein.
Veins are formed from ____, which are formed from capillaries.
Venules
List the four components of a blood vessel.
- Endothelium
- Elastic layer
- Smooth muscle
- Connective tissue
If fatty plaques build up in the ____, it can become stiffer and tougher.
Endothelium
A buildup of fatty plaque in the endothelium results in a rise in…
Blood pressure
____ have a thick elastic layer to enable stretching.
Arteries
____ can stretch and recoil in response to the pumping of blood, maintaining pressure in the circulatory system.
Arteries
Veins have less ____ and ____ than arteries.
Smooth muscle and elastic tissue
Blood pressure is ____ after blood exits the capillaries.
Lower
____ are only large enough to allow red blood cells to travel single file.
Capillaries
In the capillaries, some ____ leaves the blood to carry materials to the cells.
Plasma
Capillaries may have different ____ depending on the number of pores in their endothelial cells.
Permeabilities
List the three classes of capillaries based on permeability.
- Capillary
- Fenestrated capillary
- Sinusoid
Capillaries can regulate heat exchange via…
Vasoconstriction and vasodilation
True or false:
Blood pressure in veins is insufficient to return blood to the heart.
True
The ____ is made of skeletal muscle surrounding veins that contracts to help blood move.
Venous pump
____ open and close in response to muscle contraction, pushing blood towards the heart.
Venous valves
Together, the ____ and ____ force blood in the veins to flow only in one direction.
Venous pump and venous valves
____ may filter out of the capillaries and become lymph.
Blood plasma, water, solutes
Larger molecules called ____ do not diffuse out of the capillaries.
Plasma proteins
The fact that plasma proteins do not diffuse out of the capillaries creates osmotic pressure, causing…
Most of the water that diffused out to reenter the capillaries
True or false:
Not all of the fluid that diffused out of the capillaries reenters via osmosis.
True
The lymphatic system is located in close proximity to the…
Circulatory system
Excess lymph drains into the…
Blind-ended lymphatic capillaries
Lymphatic capillaries merge to form…
Lymphatic vessels
Lymphatic vessels converge at ____ located throughout the body.
Lymph nodes
Larger lymphatic vessels converge through ducts into the ____ and then into the heart.
Main venous pathways
