Human Bio Test 2

What is the heart

The pump that moves blood around the body, enclosed in a membrane called pericardium, made of cardiac muscle. Separated by the septum (left and right sides of heart)

What is an atria

Top most chamber of the heart where blood is received from the body and lungs.

What are ventricles

The lower chambers of the heart that pump blood to the lungs and the rest of the body.

Steps of movement

the Superior Vena Cava and Inferrer Vena Cava right atrium receives deoxygenated blood, which goes to the right ventricle (through the tricuspid valve (right atrioventricular valve)) which pumps blood into the Pulmonary artery(pulmonary valve(right semilunar valve))(to the lungs where blood becomes oxygenated). Blood then goes to the pulmonary veins, to the left atrium, (Mitral, Biscupid or left atrioventricular valve) to the left ventricle and then up the Aorta (Aortic valve, left semilunar valve) to the rest of the body.

Left side is thicker, needs to be stronger to pump more blood (oxygenated)

Valves

ensure blood can only flow in one direction

Atrioventricular valve

between atria and ventricles. (Tricuspid and Mitral/Biscupid valve)

Semilunar valve

between ventricle and next stage, has 3 cusps

(vein/artery) (pulmonary valve and aortic valve)

Chordae tendineae

The thin tissue held by atrioventricular valve tissue, a tendon attached to the heart on pupillary muscles. Prevent valves turning inside out

Blood vessels

pumped by the heart, carries blood to cells or lungs, same blood flows through the heart constantly, called circulation. Composed of Arteries, Capillaries and veins.

What is an artery

Blood vessels that carry blood away from the heart, oxygenated, smooth muscle, elastic fibres, thick muscular walls, stretch for extra blood.

Muscles can contract to reduce blood flow to an organ, Vasoconstriction. occurs when cold.

Vasodilation occurs when muscles relax to increase blood flow, happens when warm

smaller arteries called arterioles, supplies blood to capillaries

Cellular respiration makes waste (CO2 and Lactic acid) act a vasodilators.

What is a vein

Blood vessels that carry blood towards the heart, deoxygenated.
Inferior: blood from below the heart.
Superior: blood from above the heart. Thin elastic walls, don’t have muscular walls. capillaries join to make venules.
LOW BLOOD PRESSURE.

has valves

What are capillaries

Link between Arteries and Veins, microscopic blood vessels that are 1 cell thick. They provide blood to cells and cells gain requirements and past waste into blood.

Blood Flow

When exercises we need more oxygen and produce more waste, this means the heart needs to increase change the output of blood from the heart and change diameter of the blood vessel to supply blood to tissue.

BLOOD:

TRANSPORTS: oxygen +nutrients + hormones to cells, CO2 and waste away
MAINTAINS: pH, water content, ion concentration of body fluids + salt + body temp
DISTRIBUTE: heat + maintain body temp
PROTECTS: against disease (white blood cells)
CLOTTING: to prevent blood loss

Cardiac Cycle

The sequence of events that occurs on one complex beat of the heart. Heart contracts: systole, pumping phase. Heart relaxes: diastole, filling phase.

Cardiac output

Volume of blood pumped from 1 ventricle in 1 min

Heart rate

Number of beats per minute

Stroke volume

volume of blood forced out ventricles with each contraction

blood pressure

Pressure of circulating blood against walls of arteries. 120/80. systolic pressure (measures pressure in arteries when the heart contracts)/diastolic pressure(measures pressure when the heart relaxes)

Structure of blood

55% plasma, transports medium around body, mixture of H2O + dissolved substances, hormones, proteins, antibodies.

45% Formed elements- 40-45%(haematocrit) Erythrocyes (RBC)
-Leucocytes (WBC). | 1%
-Thrombocytes- less | less than 1%

Erythrocytes

Red Blood Cells
40-45% of blood (haematocrit), BICONCAVE shape to increase Surface Area, transports oxygen, contians antigens on surface. Antigen + anitbody= simulated immune response

No nucleus = flexibility, limits life span
more room for haemoglobin (protein in RBC that carries oxygen)

Leucocytes

White Blood Cells
Fight infection, larger than RBC, Different with own structure + function:
-Neutrophlis: enzymes that digest pathogens
-Monocytes: macrophages that engluf pathogens
-Lymphocytes: Immune response

Thrombocytes

Platelets
Less than 1%, small fragments of cell with no nucleus, formed in bone marrow and lasts 7 days.
Form scaffold for coagulation of blood and forms into a clot

Transport of Oxygen

97% Haemoglobin, 3% dissolved in oxygen, Oxyhaemoglbin = HbO2

Carbon Dioxide 22% carbaminohaemoglobins, 70% bicarbonate ions carried in plasma

Nutrients + waste:
dissolved + transported in plasma, glucose, vitimins, metabolic waste, urea, inorganic nurtients transported as ions Na+ K+

Blood Clotting

1:Vasoconstriction- arteries constrict
2: Roughness- creates surface for platelets to stick
3:Platelet plug- platelets tick to rough internal surface, forms a plug, prevents blood loss, also release chemicals that attract other platelets, enhances vasoconstriction.
4:Clotting factors- soluble plasma proteins initiating clotting
5:Fibrinogen- soluble fibrin is converted into insoluble threads
6:Blood clot- Fibrin thread mesh (blood clot) that traps blood cells, platelets and plasma, this clot sticks to the damaged blood vessel and holds the clot in position
7:Clot retraction- slow process, network of fibrin threads contract, pulling the edges of the damaged blood vessel together
8:Scab- Clot dries, forming a scab over the wound that will eventually fall off.

Antigen

sugars on blood or protein molecules on the surface of erythrocytes that can stimulate an immune response

Antibody

Protein produced by the immune system in response to exposure to an antigen (in blood to join antigen

The Lymphatic system

collects some of the fluid that escapes tissues intercellular spaces to return the fluid back into the circulatory system.



-Role in internal defence against disease causing organism.
-Transports large molecular compounds (enzymes + proteins) from manufacture site to the blood stream
-high pressure in the capillaries makes the fluid in blood to be forced through capillary walls into tissue

Structure of the lymphatic system

-Network of lymph capillaries joined by larger lymph vessels (lymphatic vessels/lymphatics)
-Lymph nodes are located long the length of lymph vessels

Lymph vessels

Originate as blind end tubes between cell tissues
-Larger and more permeable than blood capillaries
-Networks joins to form two lymphatic ducts that empty into large veins in the upper chest
-Has valves to stop back flow when pressure drops
-moved by contraction of smooth and skeletal muscles.
-Flows in one direction, unidirectional, permiable
→

Lymph

the fluid that escapes capillaries and is returned back to the circulatory system via the lymphatic system

Vasoconstriction

arteries constrict, step 1

Roughness

creates surface for platelets to stick, step 2

Platelet plug

platelets tick to rough internal surface, forms a plug, prevents blood loss, also release chemicals that attract other platelets, enhances vasoconstriction. STEP 3

Clotting factors

soluble plasma proteins initiating clotting Step 4

Fibrinogen

soluble fibrin is converted into insoluble threads

Step 5

Blood clot

Fibrin thread mesh (blood clot) that traps blood cells, platelets and plasma, this clot sticks to the damaged blood vessel and holds the clot in position
Step 6

Clot retraction

Slow process, network of fibrin threads contract, pulling the edges of the damaged blood vessel together
Step 7

Scab

Clot dries, forming a scab over the wound that will eventually fall off.
Step 8

Lymph Nodes

Bean shaped, swell when infection occurs, found in the neck, armpit and groin, its where white blood cells where WBC are made:

lymphoid tissue:

lymphocytes: apart of immune response

macrocytes, engulf + destroy particles through phagocytosis

plasma cells, produce chemicals to destroy pathogens