Lecture #20

Question 1

What is diffusion?

Answer 1

Random (Brownian) movement caused by thermal energy

Question 2

When is diffusion fast or slow?

Answer 2

Slow in long distances; Fast in short distances

Question 3

What determines where the molecules go through diffusion?

Answer 3

High concentration to Low concentration

Question 4

When does diffusion across a membrane work best; and when does it not work well?

Answer 4

When the membrane of a cell can be completely surrounded by the ion/molecule trying to diffuse; does not work well with thick walls of cells (tissue) because fewer cells can interact with environment

Question 5

What does circulation do and why is it effective?

Answer 5

Circulation speeds up transport of ions and molecules. Essentially, it just moves things around the body.

Question 6

What do animals have when they don’t have circulatory systems?

Answer 6

Gastrovascular cavities

Question 7

What are gastrovascular cavities?

Answer 7

They are open areas (cavities) that place many cells in contact with the environment.

Question 8

Where are gastrovascular cavities present/not present?

Answer 8

They are present when animals do not have circulatory systems

Question 9

What kind of tissue do creatures with gastrovascular tissues have and why?

Answer 9

Thin creatures since tissues are thin enough to allow sufficient diffusion to all cells

Question 10

Describe how capillaries work in circulatory systems? What purpose do they serve?

Answer 10

Capillaries are the part of the circulatory system that transports blood to every cell. This blood contains all the ions, molecules, and nutrients that every cell in our body needs to survive. Ions and small molecules within the blood diffuse across blood vessel cell membranes into skeletal muscle. Red blood cells move single file fashion through capillaries.

Question 11

What are the two types of circulatory systems?

Answer 11

Open and Closed

Question 12

What are the 2 main characteristics of an open circulatory system?

Answer 12

Vessels don’t form complete circuit ; Blood is called hemolymph since it mixes with interstitial fluid in the body

Question 13

What is the main characteristic of closed circulatory systems?

Answer 13

Blood is enclosed in vessels meaning blood never exits vessels

Question 14

What is the water vascular systems and what is its main characteristic?

Answer 14

Water vascular system is a circulatory system using sea water instead of blood or hemolymph. Main characteristic: uses hydraulic system for pretty much everything, even moving itself.

Question 15

How do most pathogens enter the body and why?

Answer 15

They enter through the circulatory system (blood) since it has access to essentially every cell in the body that way (do the most damage)

Question 16

What are the 6 things that circulatory systems move (excluding pathogens)?

Answer 16

Oxygen, sugars, hormones, antibodies, carbon dioxide, and urea

Question 17

What is blood made of?

Answer 17

Is a tissue made of cells, platelets, and plasma

Question 18

What are the two types of cells in blood?

Answer 18

Erythrocytes and leukocytes

Question 19

What are erythrocytes and how do they work?

Answer 19

They are red blood cells that transport oxygen. They are packed with hemoglobin, a protein that binds to 4 oxygen each and can release oxygen molecules when in an environment with little oxygen

Question 20

How are red blood cells shaped and why?

Answer 20

They have a concave shape that gives them high SA/V ratio.

Question 21

What are leukocytes and how do they work?

Answer 21

They are white blood cells (immune cells) that defend against pathogens. They also have weirdly shaped nuclei whereas red blood cells have no nuclei.

Question 22

Why do red blood cells not live that long?

Answer 22

They have no nuclei (90-100 days lifespan)

Question 23

What are platelets and what is their function?

Answer 23

They are tiny fragments of red blood cells that form clots to aid in injury. hormone is sent out that attracts platelets.

Question 24

What is plasma and what is its purpose?

Answer 24

Plasma is a fluid within blood that is 95 percent water and carries everything that blood is transporting (except for oxygen) including ions, glucose, hormones, and proteins.

Question 25

How is blood transported?

Answer 25

Blood is transported in vessels.

Question 26

What are arteries? What are its 2 characteristics?

Answer 26

Vessels that take blood away from the heart. They have thin diameter to speed up blood movement and covered in thick layer of smooth muscle to open and close the arteries.

Question 27

What are veins? What are their two characteristics?

Answer 27

Veins bring blood towards the heart. They have big radius meaning low pressure. They also have valves that prevent back flow of blood when it stops moving between heart pumps

Question 28

What are capillaries?

Answer 28

The site of gas/solute exchange. Where the work of the circulatory systems happen. They are one blood cell thick, so the net movement is very fast.

Question 29

What are the three types of hearts that an organism can have?

Answer 29

Two chambered, three-chambered, and 4 chambered

Question 30

What type of circulation (circulatory system) does each type of heart have?

Answer 30

2-chambered- single circulation ; 3-chambered and 4-chambered-double circulation

Question 31

Describe single circulation in a 2 chambered animal?

Answer 31

One circuit; blood goes straight from lungs into rest of the body, does not stop at the heart to spread blood quickly throughout the body.

Question 32

Describe double circulation in a 3 chambered animal?

Answer 32

2 circuits; one dedicated to respiratory functions (bringing blood to lungs for oxygen/deoxygenate, and one for body/systematic functions (transporting O2 and nutrients to cells). Blood goes from heart to lungs, back to heart, and to the rest of the body.

Question 33

Describe double circulation in a 4 chambered animal

Answer 33

4 chambered animal has 2 ventricles, meaning complete separation of the two circuits and efficient movement of the blood. Also, blood going from lungs back into heart means blood can move quickly throughout the body.

Question 34

What is the main difference between three chambered and four chambered hearts?

Answer 34

4 chambered has two ventricles, 3 chambered only has one. This means, in 3 chambered hearts, one ventricle is pumping some blood to body and some blood to lungs, meaning some blood doesn’t get oxygenated before getting back into body.

Question 35

What is unique about the evolution of 4 chambered hearts?

Answer 35

They evolved twice, in mammals and archosaurs