Human Biology > Circulatory System > Flashcards

Circulatory System Flashcards

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1
Q

What is the key function of the Circulatory System?

A

Transports oxygen, nutrients, and waste between the internal enviroment and body cells

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2
Q

State the three levels of gas exchange in the circulatory system and their components (structure and function)

A

Cell Level - Erythrocytes (red blood cells) transport oxygen via haemoglobin, while leucocytes (white blood cells) help protect against infections
Tissue level - Capillaries allow for the exchange of gases, nutrients, and wastes between the blood and body tissues
Organ level - The ehart pumps blood through the artieries, veins, and capillaries, ensuring continuous circulation

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3
Q

State the components of blood and their functions

A

Plasma - Carries nutrients, hormones, and waste
Erythrocytes (Red Blood Cells) - Transport oxygen using haemoglobin and facilitate carbon dioxide removal
Platelets - Involved in clotting to prevent excessive blood loss
Leucocytes (white blood cells) - Provide immune defence against infections and foreign invaders

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4
Q

State the role of the Lymphatic System

A

-Returns tissue fluid (lymph) to the circulatory system to maintain blood volume
-Contains lymph nodes, which fliter pathogens and house immune cells (lymphocytes) that help fight infections

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5
Q

State three functions of blood

A

-Transport materials around the body
-Vital for immune system (Leucocytes)
-Regulates body temperature

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6
Q

State the structure of blood

A

Plasma: liquid part
Formed elements: the non-liquid part, consisting of erythrocytes (red blood cells), leucocytes (white blood cells) and Thrombocytes (platelets)

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7
Q

State the components of Plasma

A

-Mixture of water with dissolved substances (sugars, salts)

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8
Q

What is the plasmas function (purpose)

A

Transport components of blood throughout the body (cells, nutrients, wastes, hormones etc.)

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9
Q

State the characteristics of Erythocytes

A

-Most abundant cells in the body (take up 40-45% of blood volume)
-Cells bioncave shape
-No nucleus; more flexible = can move through blood vessels, life span 120 days
-Transport oxygen from the lungs to the body’s cells

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10
Q

What are Red Blood Cells scientifically called?

A

Erythrocytes

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11
Q

State the characteristics of Leucocytes

A

-Protect the body from infection
-Make up on 1% of blood volume
-Larger than Erythrocytes

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12
Q

State a few of the different types of Leucocytes

A

-Neutrophils - most common, contain enzymes to digest pathogens
-Monocytes - form other cells, including macrophages (they engulf pathogens or aged/damaged cells by phagocytosis)
-Basophils - responsible fore allergic reactions (produce heparin and histamine to defencd tha body against parasites and bacteria)
-Eosinophils - lead to inflammatory responses (respond ti larger parasites, worms)

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13
Q

What are White Blood Cells scientifically known as?

A

Leucocytes

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14
Q

State the characteristics of Thrombocytes

A

-Small fragments of cells
-Used when a blood vessel is damaged

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15
Q

How do Thromocytes help injured blood vessels?

A

They adhere to the lining to form a scaffold for the coagulation of the blood to form a clot

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16
Q

What are Platelets scientfically known as?

A

Thrombocytes

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17
Q

How are nutrients and wastes transported through the body?

A

Nutrients and wastes are dissolved in the blood plasma, than transported around the body as necessary

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18
Q

State some organic nurtients found in blood plasma

A

-Glucose
-Vitamins
-Amino Acids
-Fatty Acids
-Glycerol

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19
Q

What are metabolic wastes and why do they need to leave the body?

A

They are substances produced by cells that are harmful and need to be transported out

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20
Q

What is the purpose of blood clotting?

A

Helps to minimise blood loss and prevent infection after an injury that causes damage to blood vessels.

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21
Q

What are the steps to blood clotting?

A
  1. Vasconstriction
  2. Platelet plug
  3. Coagulation
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22
Q

What is Vasconstriction?

A

is the narrowing of the blood vessels resulting from contraction of the muscular wall of the vessels, in particular the large arteries and small arterioles
-Decreases blood flow
-Increases blood pressure
-Increases body temperature
-Caused by cold, dehydration, adrenaline
-Skin becomes pale + cold

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23
Q

What is Platelet Plug?

A

In response to the injury, the body activates platelets. At the same time, chemical signals are released from small sacs in the platelets to attract other cells to the area. They make a platelet plug by forming a clump together.

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24
Q

What is coagulation?

A

Coagulation, also known as clotting, is the process by which blood changes from a liquid to a thicker, gel-like state, forming a clot to stop bleeding and initiate wound healing.

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25
Explain the Fibrin Clot
When a blood vessel becomes injured, the coagulation factors or clotting factors in the blood are activated. The clotting factor proteins stimulate the production of fibrin, which is a strong and strand-like substance that forms a fibrin clot. For days or weeks, this fibrin clot strengthens and then dissolves when the injured blood vessel walls close and heal
26
Why is Blood clotting crucial?
It prevents further blood loss from injured blood vessels
27
What is a blood clot?
A jelly-like mass that forms at the site of a wound to stop bleeding (consists of a mesh of long, stretchy protein fibres, and trapped blood cells)
28
What is a clot called when formed within a blood cell?
Thrombus
29
What can happen if a Thrombus comes loose?
It can lodge in a vital blood vessel in the heart or brain causing a heart attack or stroke
30
What is the inflammatory response?
Inflammation is the body’s response to harmful substances, injury, or irritants. Typically the affected area becomes red, tender, hot and swollen.
31
State the inflammatory response
When the body is injured, infected or exposed to irritants, radiation, or extreme temperatures, a complex chemical response is initiated This response involves several compounds being released in the affected area. These substances both interact and have specific outcomes (i.e. the inflammatory response)
32
Name the two chemicals released during an inflammatory response
Histamine - released by mast cells, which causes local dialtion and increased permeability of the blood vessels and increases mucus secretion - anti-histamine drugs reverse this drug Heparin - also released by mast cells, thins blood
33
What are the role of the valves?
They ensure the direction of blood flow is controlled to move in one direction only (the four valves work together)
34
Why does the heart make a "lubb dubb" sound?
It is a result from the heart valves snapping shut inside the heart.
35
How are the atrioventricular (valves between the ventricle and atriums) valves held?
They are held in position by strong tendons, the chordae tendinae (tendineae)
36
What regulates the heart beat?
The heart contains specialised conductive tissue which regulates the heartbeat.
37
What is the sinoatrial Node (SA node or pacemaker)
A cluster of specialised cardiac cells in the wall of the right atrium which initiates the heartbeat
38
What is the atrioventricular node (AV node)
The secondary pacemaker which regulates the beating of the ventricles
39
What are ateries?
muscular blood vessels that carry blood away from the heart
40
What are aterioles?
small arteries that direct blood flow to various tissues
41
What are capillaries?
microscopic blood vessels that connect arterioles and venules. They enable the exchange of substances between blood and surrounding tissues
42
What are Venules?
Small veins
43
What are veins?
Blood vessels that carry blood toward the heart
44
What is pulomary circulation?
Takes deoxygenated blood from the right ventricle to the lungs and returns oxygenated blood to the left atrium
45
What pumps the Pulmonary Circulation?
The right ventricle
46
What is Systemic Circulation?
takes oxygenated blood from the left ventricle to all the tissues of the body and returns deoxygenated blood to the right atrium
47
What pumps the systemic circulation?
The left ventricle
48
What is the Lumen?
The cavity or channel within a tube or tubular organ such as a blood vessel or the intestine
49
State the characteristics of the Lumen in Veins
Relatively thin walls and large lumen
50
State the characteristics of the Lumen in Arteries
Relatively thick, muscular walls and small lumen
51
Name the Granulocytes
Eosinophils Basophils Neutrophils
52
Name the Agranulocytes
Lymphocytes Monocytes
53
What are granulocytes
Granulocytes are a type of white blood cell characterized by granules in their cytoplasm, and they are crucial for the body's innate immune response, particularly against bacterial and fungal infections.
54
What are Argranulocytes
Agranulocytes are a type of white blood cell (leukocyte) that lack visible granules in their cytoplasm, vital role in the immune system, helping to defend the body against infection and disease.
55
How is oxygen transported in the blood?
97% binds to haemoglobin forming oxyhaemoglobin in erythrocytes; 3% dissolves in plasma
56
How is carbon dioxide transported in the blood?
70% as bicarbonate ions in plasma, 22% bound to haemoglobin (carbaminohaemoglobin), and 7-8% dissolved in plasma
57
Why does oxygen move into red blood cells in the lungs?
Due to the higher concentration of oxygen in the alveoli than in the blood — it diffuses down the concentration gradient.
58
What is the cardiac cycle?
The sequence of events in one complete heartbeat, including systole (contraction) and diastole (relaxation).
59
What is cardiac output and how is it calculated?
The amount of blood pumped by one ventricle per minute; calculated as stroke volume × heart rate
60
How can the body adjust blood flow?
By changing cardiac output or altering blood vessel diameter through vasoconstriction or vasodilation
61
What are two primary functions of the lymphatic system?
1) Returns excess tissue fluid to the bloodstream 2) Provides immune protection by filtering pathogens
62
How does lymph move through the lymphatic system?
Through smooth muscle contraction, skeletal muscle squeezing, and valves to prevent backflow.
63
What are lymph nodes and what do they do?
Bean-shaped structures that filter lymph and contain leucocytes (e.g. macrophages and lymphocytes) to trap pathogens.
64
What determines your ABO blood type?
The presence or absence of A and B antigens on the surface of red blood cells.
65
Why is blood type O a universal donor?
It lacks A and B antigens, so it won’t trigger anti-A or anti-B antibodies in recipients.
66
Why is blood type AB a universal recipient?
It has both A and B antigens and no anti-A or anti-B antibodies.
67
What happens in a mismatched blood transfusion?
Agglutination — antibodies react with donor antigens causing clumping, which can be fatal.
68
What is the Rh factor?
A blood group antigen; people without it can produce anti-Rh antibodies if exposed.
69
What are the structural components of artery walls?
Tunica Interna: Present Tunica Media: Well developed (thick, muscular, and elastic) Tunica Externa: Relatively thin Lumen: Small and narrow to maintain high pressure
70
What are the structural components of capillary walls?
Tunica Interna: Present Tunica Media: None Tunica Externa: None (Capillaries are only one cell thick to allow for exchange of substances) Lumen: Very narrow (just wide enough for red blood cells to pass through single file)
71
What are the structural components of vein walls?
Tunica Interna: Present Tunica Media: Relatively thin Tunica Externa: Well developed Lumen: Wide to accommodate low-pressure, slower blood flow; often contains valves
72
What is Vasodilation?
Widening of blood vessels by relaxation of smooth muscle in vessel walls -Increases blood flow -Lowers blood pressure -Decreases body temp. -Caused by heat, CO2, hormones, decreased oxygen -Skin become red + warm
73
PULMONARY CIRCULATION: What is the primary function and key pathway?
Function: To carry deoxygenated blood to the lungs for gas exchange (CO2 out, O2 in) and return oxygenated blood to the heart. Pathway: Right Ventricle -> Pulmonary Artery -> Lungs (Capillaries) -> Pulmonary Veins -> Left Atrium
74
SYSTEMIC CIRCULATION: What is the primary function and key pathway?
Function: To carry oxygenated blood and nutrients to all body tissues and return deoxygenated blood (with CO2) to the heart. Pathway: Left Ventricle -> Aorta -> Systemic Arteries -> Body Tissues (Capillaries) -> Vena Cavae -> Right Atrium
75
Outline the sequence of events in regard to the cardiac cycle
1. Diastole (General Relaxation): Both the atria and the ventricles are briefly in diastole (relaxation) simultaneously. 2. Atrial Filling: During this phase of relaxation, the atria fill with blood. 3. Ventricle Filling (Passive): The ventricles begin to receive blood because the valves located between the atria and ventricles (atrioventricular valves) are open. 4. Atrial Systole (Contraction): The atria contract (atrial systole), which forces the remaining blood into the ventricles. 5. Ventricular Systole (Contraction): Following atrial contraction, the ventricles contract (ventricular systole). During this period, the atria relax and begin to refill. 6. Ejection: The ventricular contraction forces blood into the arteries (the aorta and pulmonary artery). (The closing of the atrioventricular valves and then the semilunar valves gives the heartbeats their characteristic 'lub dub' sound).
76
What is the equation to determine how fast blood travels around the body?
cardiac output = stroke volume x heart rate
77
Outline the role of the Thrombocytes (platelets) in the clotting process
-Very small cell fragments with no nucleus -When a blood vessel is injured, the normally smooth internal walls become rough, causing thrombocytes to adhere to the lining -build up a plug at the injury site (reduce blood loss) -Also release substances that act as vascoconstrictors (enhance and prolong the constriction of the damaged vessels) -Form a scaffold for the coagulation of the blood (form a clot)
78
Outline the role of the Plasma in the clotting process
-Liquid part of the blood, makes up approx. 55% of blood volume -Serves as the medium that transports necessary compents, including the chemical substances required for coagulation -Contains the clotting factors (chemical substances)
79
Outline the role of the Clotting Factors in the clotting process
-Large number of chemical substances present in the blood plasma -Responsible for iniating the complex series of reaction involved in coagulation -Results in final formation of fibrin
80
Outline the role of the Fibrin in the clotting process
-Insoluble protein formed during the coagulation process -Createds threads that form a mesh -The mesh traps blood cells, thrombocytes, and plasma, forming the stable bulk of the clot (thrombus) -Fibrin threads stick to the damaged blood vessels
81
Outline the role of the Eyrthrocytes and Leucocytes in the clotting process
-Physically trapped within the fibrin mesh alongsid thrombocytes and plasma to minimise blood loss and form the completed thrombus
82
Why can't B- blood recieve A+ blood?
ABO incompatibility: -a person with B- blood has B antigens on their eyrthrocytes and naturally produces anti-A antibodies -A person with A+ blood has A antigens on their eyrthrocytes When A+ blood is transfused into a B- recipient, the recipient's existing anti-A antibodies immediately bind to the donor's A antigens, causing aggluination and destruction of donor cells Rh Incompatibility: -The recipient is Rh negative (Rh-), they do not have the Rh antigen -The donor is Rh+, meaning their eyrthrocytes do possess the Rh antigens Rh- individuals do not initally have anti-Rh antibodies, but will form them after exposure to Rh+ blood. Causes delayed immune reaction as anti-Rh antibodies attack donor cells. Result: Ultimately the foreign cells will clump together, or agglutinate, and disintegrate. 1. Immediate aggulation due to the existing anti-A antibodies reacting with the donor's Antigen A 2. Delayed or sensitising reaction involving the potential production of anti-Rh anitbodies reacting with the donor's Rh antigens
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