exam 4 circulatory system

Why did circulatory systems evolve?

Diffusion became too slow in larger organisms

What limits diffusion?

Distance and thickness

What do circulatory systems transport?

Oxygen, nutrients, waste

What are capillaries?

Thin blood vessels for exchange

Why are capillaries one cell thick?

To maximize diffusion

To maximize diffusion

Slows down

Why is slow flow important?

Allows more exchange time

What do simple organisms use instead of circulatory systems?

Diffusion / gastrovascular cavity

Why did the heart evolve?

To generate pressure to move blood

What is cardiac muscle specialized for?

Coordinated contraction

What are intercalated discs?

Connections between heart cells

What is an open circulatory system?

Blood directly contacts tissues

What is a closed circulatory system?

Blood stays in vessels

Which system is more efficient?

Closed

How many chambers does a fish heart have?

2

How many chambers does an amphibian heart have?

3

How many chambers do mammals have?

4

What is the septum?

Wall separating heart chambers

What is double circulation?

Two circuits (pulmonary + systemic)

arteries

carry blood away from heart, high pressure

veins

carry blood back to the heart, low pressure

ventricle

pump blood out

atria

recieve blood

right atrium

from body

left atrium

from lungs

right ventricle

to lungs l

left ventricle

to body

what ventricle is the thickest?

left ventricle because it pumps blood to entire body (highest pressure)

pulmocutaneuous

combinations of using skin and lungs for gas exchange, only seen in amphibians

What is double-loop circulation?

Blood passes through the heart twice per cycle

What are the two circuits?

Pulmonary and systemic

What is the function of the pulmonary circuit?

Gas exchange

What is the function of the systemic circuit?

Deliver oxygen and nutrients

Why is double-loop circulation efficient?

Separates oxygenated and deoxygenated blood

pulmonary circuit

Blood flow between heart and lungs

Where does pulmonary circulation start?

Right ventricle

Where does it end?

Left atrium

What happens in the lungs?

Gas exchange (O₂ in, CO₂ out)

Which artery carries deoxygenated blood?

Pulmonary artery

Which vein carries oxygenated blood?

Pulmonary vein

What is the systemic circuit?

Blood flow between heart and body

Where does it start? systematic circuit

Left ventricle

Where does it end? systematic circuit

Right atrium

What does systematic circuit remove?

CO₂ and waste

What is the main artery in systemic circulation?

Aorta

What is arterial blood?

Oxygen-rich blood

What is venous blood?

Oxygen-poor blood

What does arterial blood deliver?

Oxygen and nutrients

What does venous blood carry?

Carbon dioxide and waste

Where does venous blood go?

Back to the heart

Which system flips oxygen levels?

Pulmonary system

What are the main components of blood?

Plasma and cells

What does plasma do?

Transports substances

What do red blood cells do?

Carry oxygen

What do white blood cells do?

Fight infection

What do platelets do?

Clot blood

Where are blood cells made?

Bone marrow

What is the stem cell for blood cells?

Hemocytoblast

What is a lineage?

A developmental pathway of cells

What is the myeloid lineage?

Produces RBCs, platelets, and many WBCs

What is the lymphoid lineage?

Produces lymphocytes

What cells come from lymphoid lineage?

B cells, T cells, NK cells

What is systole?

Contraction of the heart

What is diastole?

Relaxation of the heart

What do valves do?

Prevent backflow which is blood flowing in the wrong direction

Where is pressure highest?

Aorta

Why does pressure drop?

Friction + branching

Why does blood slow in capillaries?

Increased cross-sectional area

Why is slow flow important?

Allows exchange

What helps veins return blood?

Valves

What prevents backflow?

Valves

What is cross-sectional area?

Total area of vessels

What happens when cross-sectional area increases?

Flow slows down

What is atherosclerosis?

Plaque buildup in arteries

What happens to the lumen in atherosclerosis?

It narrows

What are foam cells?

Macrophages filled with cholesterol

What does reduced blood flow cause?

Less oxygen to tissues

What can blockage in the heart cause?

Heart attack

What can blockage in the brain cause?

Stroke

Arteriosclerosis

Artery stiffens (hardening)

What does an ECG measure?

Electrical activity of the heart

Who invented the first ECG method?

Augustus Waller

What does the P wave represent?

Atrial contraction

What does the QRS complex represent?

Ventricular contraction

What does the T wave represent?

Heart relaxation

What does the lymphatic system do?

Fluid balance + immune defense

What fluid does the lymphatic system carry?

Lymph

Does the lymphatic system have a pump?

No

How do the systems work together? lymphatic system and circulatory

Lymph returns excess fluid to blood

gastrovascular cavity

A single-opening digestive compartment

What fluid is in an open system?

Hemolymph

What fluid is in a closed system?

Blood

what is hemolympth

blood and other other fluids found in an open circulatory system

Which animals have open circulatory systems?

Arthropods and most mollusks

How do insects get oxygen?

Tracheal system

Do amphibians have mixing of blood?

Yes

pulmocutaneous circuit

to lungs and skin

systemic circuit

to body

what is the biggest difference in between reptile blood circuits and reptile blood circuits?

Better separation of blood than amphibians, but not perfect, they have incomplete septum (flap of tissue)