Biology Heart + immunity + cells test review

6.1 defense against infectious disease

Innate immunity (non-specific immunity)

• these are barriers against infection and prevent entry of any pathogen

• does not target specific pathogens

• EX: the skin provides a physical barrier to prevent entry of pathogens

pathogen

• any biological agent that causes illness or disease

• typically, a virus (flu), bacteria(e-coli), fungi (athletes’ foot) or protists (malaria)

sebum

• oily/waxy substance produces by the skins sebaceous glands

• slightly acidic to prevent infection

Mucous membranes

• openings (orifices) produce mucus to trap pathogens

• contains lysozyme an anti-bacteria enzyme

Phagocytes

• a type of white blood cell

• provide nonspecific immunity (do not learn to recognize and attack specific pathogens

• they exhibit ameboid movement, recognize foreign pathogens, engulf them by endocytosis, then digest the pathogens using lysosomes

• at the sight of injury, inflammation will cause the phagocytes to leak out of the capillaries to fight off infection.

blood contains:

• white blood cells

• erythrocytes (red blood cells)

• platelets

• clotting factors

blood clot formation

1. vessel is damaged

2. exposed molecules in damaged vessel cause binding of platelets

3. binding activates the platelets

4. these activated platelets release clotting factors

5. fibrin forms strands

6. these fibrin strands form a mesh that stabilizes the clots, and captures more erythrocytes, forming a clot

prothrombin

• is a zymogen- a precursor to an active enzyme

• is inactive however becomes active thrombin

• this thrombin is converted to a soluble fibrin

• the soluble fibrin becomes insoluble

• this become an insoluble polymer that is a netlike structure that causes the clot to from

adaptive immune response 6.1.2

antigens

• proteins found on cells that are used for recognition

• most are glycoproteins

• each type of pathogen will have specific antigens. the adaptive immune system learns to recognize these antigens

antibodies

• proteins made by the immune system, that bind to specific antigens

• they are monoclonal- specific to one antigen and made by one type of parent cell

• (same recognition process as to why different blood types are incompatible)

• the main weapon against pathogens

lymphocytes

• cells of the adaptive immune system that cooperate to produce antibodies

• travel in the blood and are also concentrated in lymp nodes

• humans have around 1000-4800 lymphocytes

B and T cells

• types of lymphocytes

• many b cells are stored in lymph nodes with genetic instructions to make a specific type of anti-body

• they wait dormant ready to make antibodies if/when infiltration occurs

when infiltration occurs ……

1. the pathogen enters and the macrophage engulfs it

2. the macrophage deactivates it and it presents the antigen to a helper T Lymphocyte

3. these helper T cells activate specific B cells

4. the B cells divide by mitosis making clones (these clones are plasmacells)

5. Plasma cells make antibodies to fight off the infection

this process

• occurs in the lymphnodes

after this process….

• some B cells remain

• these are called memory cells and may have a very long-life span

• retaining memory cells provides immunity

• vaccinees aim to form memory cells without causing disease

Types of Vaccines

1. Attenuated virus- contains the weakened virus that can replicate but not cause disease

2. inactivated virus- the bacteria is killed, or virus cannot reproduce

3. subunit virus- contains only the antigen

4. mRNA virus- contains mRNA which our cells use to make the appropriate antigen (used this in covid)

Penicillin

• is a non-competitive inhibitor and targets bacterial cell walls therefore has no effect on human cells

Zoonosis

• most pathogens infect only one host species however sometimes an infection can cross species barriers

• these are Zoonotic infections (like the bird flu)

Industrial antibody production

• monoclonal antibodies (mAB’s) are used for diagnosis

  1. inject an animal with antigens (usually a rat)

  2. the animal will make plasma cells

  3. harvest the plasma cells from the spleen

  4. using a cancer cell to splice the antibody cell

  5. this is a hybridoma cell

mAB’s

• are used to make pregnancy test

• HCG (human chorionic gonadotrophin) is a hormone produced in early pregnancy

• this is detected in Urine hence the pregnancy

HIV cause AIDS

• someone who is HIV positive may not may not develop aids

• HIV attacks T cells and other t cells that signal antibody production in B cells

• HIV attacks various cell types, AIDS will result is helper T cells are targeted

• over time it reduces t cell production and weakens immune system

6.2 The blood system

Blood

• 55% of total blood is Plasma (water, O2, CO2, salts, proteins, and waste)

• <1% of blood is a Buffy coat (platelets and leukocytes)

• 45% of blood is Erythrocytes (red blood cells)

circulation happens in two circuits

Pulmonary- from heart to lungs and back to the heart

systemic- from the heart to the rest of the body

arteries

• carry blood away from the heart

• contain muscle and elastic fibers that constrict and stretch to pulsate (this regulates blood flow)

veins

• carry blood to the heart

• they contain thinner walls and less muscle tissue

• they are close to skeletal muscles so they can be squeezed and allow blood flow

• that have closed valves to prevent backflow of the blood

6.3 Regulation of the cardiac cycle

Cardiac cycle

• the activity of the human heart from the beginning of a heart beat to the beginning of the next

• the cycle involves the contraction of the atria followed by the contraction of the ventricles

pace of the Cardiac cycle

• the pace is the heart rate

• heart rate is controlled by a bundle of nerves called Sinoatrial node (SA node for short)

SA node

• initiates contraction in the right atrium

• slight Dely between atrial contraction and ventricular contraction

• heart muscle is Myogenic- it will continue to beat without a nerve impulse

• brain communicates wirh the SA node to set the pace

Cardiovascular center

• Brain stem holds cardiovascular center- and receives impulses from different receptors

• communicates about the bodies Ph, blood pressure, and oxygen

• if these are low the heart beats faster, if high heart beats more normally

nerves that aid in heart rate

• vagus nerve slows heart rate

• sympathetic nerve increases heart rate

epinephrine

• the fight or flight hormone made in the adrenal gland

• SA node responds to epinephrine when in the blood

Blood pressure

Standard: 120/80

• systaltic blood pressure (top number) - measures the pressure in your arteries when your heart beats

• diastolic blood pressure (bottom number)- measures the pressure in your arteries when your heart rests between beats

Atherosclerosis

• the development of fatty tissue (atheroma) in the arterial walls

• atheroma is found on all people

occlusion

• the narrowing of arteries

• increases the risk of heart disease

• causes heart rate and blood pressure to increase

• additionally, an increased risk of blood clots therefore strokes and heart attack

• if the coronary arteries are clogged it can cause heart attacks

Risk factors of Atherosclerosis

• high LDL levels

• chronic high blood pressure

• consumption of trans fats

• may be a microbial component

identify the aorta, superior vena cava, inferior vena cava, the atriums, the ventricles, (both of the semi-lunar parts of the) pulmonary artery, pulmonary veins and the 4 valves.

answers here

capillaries

• have adaptations to allow the exchange of materials between blood and tissues

• large surface area due to branching

• venule- small vein

• arteriole- small artery

• narrow diameter and thin walls

• some are fenestrated- small holes that increase permeability

in arterials

• an increased pressure forces fluid out of the capillaries

• but large molecules remain the plasma

in venules

• a decrease in pressure allows for the uptake of fluids

the fluid that leaks out of the capillaries is

• tissue fluid

• tissue fluid allows for passive diffusion

• glucose and O2 diffuse into cells

• CO2 and cellular diffuse out of cels

• small substances and proteins remain in plasma, but amino acids may move

excess fluid

• drains into lymph ducts- have thin with gaps to increase fluid absorption

• called lymph when inside lymph duct

• similar to veins- also contain valves for one way movement of lymph fluid

• all lymph ducts converge+ lymph empties into subclavian vein to be returned to the blood supply( now called plasma)

humans and animals have a

• double circulation system to divide oxygenated blood from deoxygenated blood

bony fish have

single circulation meaning all of their blood in the fish’s heart is deoxygenated