Cardiovascular System Chapter 17&18. Blood Connective tissue composed of fluid, cells, and fragments of cells 1.Plasma: fluid part of blood straw-colored.

Cardiovascular SystemChapter 17&18

Blood

• Connective tissue composed of fluid, cells, and fragments of cells

1. Plasma:

• fluid part of blood

• straw-colored

• 55% of blood volume

Blood

2. Red blood cells: (erythrocytes)• round, disk-shaped cells• carry oxygen to cells and carbon dioxide away

attached to hemoglobin• 44% of blood volume• produced in red bone marrow of long bones• lack a nucleus once enter blood stream• only live about 120 days

Blood

3. White blood cells: (leukocytes)• 1% of blood volume• protect body from pathogens• large and many different types• contain a nucleus

neutrophils lymphocytes

eosinophils monocytes

basophils

Blood

4. Platelets:

• cell fragments

• produced in bone marrow

• remain in blood for about 7 days

• clotting with fibrin (becomes scab)

Blood Types

• Types: Red blood cells: Plasma:– IA i or IA IA A: A antigen B antibodies– IB i or IB IB B: B antigen A antibodies– IA IB AB: A and B antigens NO antibodies– i i O: NO antigens A and B antibodiesUniversal donor: Type O-negative (no antigens) is

compatible with all blood types because it has no antigens for other blood types to recognize with their antibodies

Universal Recipient: Type AB-positive has no antibodies in its plasma so it can accept any type without destroying those foreign cells

Rh factor

• Rh factor is an additional antigen found on the red blood cells and it is a separate gene from the ABO gene.

• If a person has two (+) genes for Rh or one (+) and one (-) they will test (+).

• A person will be (-) ONLY if they have two (-) because Rh(+) is dominant.

• Positive means you have the Rh antigen, negative means you don’t.

• Other minor antigens include Kell, Lewis A, Lewis B, rho, P etc. and doctors also attempt to match as many of those minor antigens as possible when selecting blood for transfusions.

Exchange of materials• Animal cells exchange material across

their cell membrane– Diffusion – Osmosis– Passive Transport– Active Transport

• If you are a 1-cell organism that’s easy!

• If you are many-celled that’s harder

In circulation…• What needs to be transported

– Nutrients• from digestive system

– Gases• O2 & CO2 from & to gas exchange systems: lungs, gills

– Wastes• waste products from cells

– water, salts, nitrogenous wastes (urea)

– Protective• immune defenses

– Antibodies and white blood cells

• blood clotting agents

– Stimulants• hormones

Closed circulatory system• Taxonomy

– Some Invertebrates• earthworms, squid,

octopuses

– Vertebrates

• Structure– blood confined to vessels

& separate from interstitial fluid

• 1 or more hearts• large vessels to smaller

vessels

• More effective at transporting fluids

closed system = higher pressures

Vertebrate cardiovascular system

• Chambered heart– Atria = receive blood– Ventricles = pump blood out

• Blood vessels– Arteries = carry blood away from heart

• arterioles

– Veins = return blood to heart• venules

– Capillaries = thin wall, exchange / diffusion • capillary beds = networks of capillaries

Blood vesselsArteries

arterioles

Capillaries

venules

Veins

artery

arteriolesvenules

veins

Arteries: Built for high pressure pump• Thick wall

• provide strength for high pressure pumping of blood

Connective tissue

Smooth Muscle• elastic recoil helps

maintain blood pressure even when heart relaxes

Veins: Built for low pressure flow

• Veins– Thinner Connective tissue– Thinner Smooth Muscle

• blood travels back to heart at low velocity & pressure

• lower pressure– distant from heart– blood must flow by skeletal muscle contractions

when we move » squeeze blood through veins

– Contains valves• in larger veins one-way valves

allow blood to flow only toward heart

Open valve

Blood flowstoward heart

Closed valve

Capillaries: Built for exchange• Small diameter

– No connective tissue or smooth muscle

• lack 2 outer wall layers • only endothelium

– enhances exchange across capillary

– This allows• exchange between blood

& cells

Controlling blood flow to tissues• Blood flow in capillaries controlled by

pre-capillary Spincters• supply varies as blood is needed• after a meal, blood supply to digestive tract increases• during strenuous exercise, blood is diverted from digestive

tract to skeletal muscles

– capillaries in brain, heart, kidneys & liver usually filled to capacity

sphincters open sphincters closed

Lymphatic system• Parallel circulatory system

– Part of Immune system• defending against infection

– collects interstitial fluid & returns to blood• maintains volume & protein

concentration of blood• drains into circulatory

system near junction of vena cava & right atrium

Lymph systemProduction & transport of WBCs

Traps foreign invaders

lymph node

lymph vessels(intertwined amongst blood vessels)

Mammaliancirculation

What do blue vs. red areas represent?What do blue vs. red areas represent?

pulmonary

systemic

systemic

Mammalian heart

Coronary arteries

to neck & head& arms

Coronary arteries

bypass surgery

AV

SL

AV

Heart valves• 4 valves in the heart

– flaps of connective tissue– prevent backflow

• AV valves – between atrium & ventricle– keeps blood from flowing back

into atria when ventricles contract• “lub”

• SL valves– between ventricle & arteries– prevent backflow from arteries into

ventricles while they are relaxing• “dub”

AV

SL

AV

Lub-dub, lub-dub• Heart sounds

– closing of valves– “Lub”

• recoil of blood against closed AV valves

– “Dub”• recoil of blood against

semilunar valves

• Heart murmur– defect in valves causes hissing sound when stream

of blood squirts backward through valve

Cardiac cycle

systolic________diastolic

pump (peak pressure)_________________fill (minimum pressure)

• 1 complete sequence of pumping– heart contracts & pumps– heart relaxes & chambers fill – contraction phase

• Systolic• ventricles pumps blood out

– relaxation phase• Diastolic• atria refill with blood

120

____

80