Lecture 25- Circulation

Question 1

True or False: The circulatory system of insects is an open system that bathes tissues directly with blood.

Answer 1

False; the circulatory system of insects is an open system that bathes tissues directly with HEMOLYMPH

Question 2

A(n) _____ is a blood vessel that carries blood away from the heart.

Answer 2

Artery

Question 3

The initiation of a heartbeat occurs at the _____.

Answer 3

Sinoatrial (SA) node

Question 4

The top chamber(s) of the heart are called ____.

Answer 4

Atria

Question 5

How can the endocrine system influence heart rate?

Answer 5

Secretion of epinephrine during acute stress accelerates heart rate
Also temperature

Question 6

True or False: Amphibians have double circulation and a four-chambered heart.

Answer 6

False; amphibians have double circulation and a THREE-chambered heart

Question 7

At the apex of the heart, the bundle branches diverge into the _____.

Answer 7

Purkinje fibers

Question 8

The bottom chamber(s) of the heart are called _____.

Answer 8

Ventricles

Question 9

What are the three layers of blood vessels from the lumen outward?

Answer 9

Endothelium → Smooth muscle → Connective tissue

Question 10

The aortic and pulmonary valves are types of _____.

Answer 10

Semilunar valves

Question 11

The _____ is a connective tissue sac that encloses the heart.

Answer 11

Pericardium

Question 12

Why do arteries have a thicker layer of smooth muscle than veins?

Answer 12

Sustain higher pressures

Question 13

How many chambers do fish hearts have?

Answer 13

Two

Question 14

What is the connective tissue surrounding blood vessels composed of?

Answer 14

Collagen fibers

Question 15

True or False: Amphibians withdraw oxygen through their skin.

Answer 15

TRUE

Question 16

____ is the body fluid between blood vessels and cells.

Answer 16

Interstitial fluid

Question 17

Impulses from the sinoatrial (SA) node travel directly to the _____.

Answer 17

Atrioventricular (AV) node

Question 18

What are the primary functions of the lymphatic system?

Answer 18

Collect & return interstitial fluid / Absorb lipids (from digestion) / Immunity

Question 19

What is lymph composed of?

Answer 19

Derived from interstitial fluid

Question 20

What are baroreceptors and what is their primary function?

Answer 20

Nerves on blood vessels that sense blood pressure and communicate with the medulla

Question 21

Oxygenated blood returns to the left atrium from the pulmonary circuit via the _____.

Answer 21

Pulmonary veins

Question 22

What is the primary function of the atrioventricular (AV) node?

Answer 22

Delays impulses from reaching ventricles immediately (which allows the atria enough time to fill)

Question 23

Where do cardiac impulses travel following the atrioventricular (AV) node?

Answer 23

Bundle branches

Question 24

True or False: The sympathetic nervous system can accelerate heart rate and the parasympathetic nervous system can decelerate heart rate.

Answer 24

TRUE

Question 25

True or False: Resting heart rate during a fever is generally slower than a healthy individual.

Answer 25

False; resting heart rate during a fever is generally FASTER than a healthy individual

Question 26

Open Circulatory System

Answer 26

Fluid= hemolymph= interstitial fluid
Heart Contractions- hemolymph-> vessels-> interconnected sinuses
Heart Relaxations- Draw hemolymph back into heart
Low pressure, low efficiency, low E
Arthropods, most molluscs

Question 27

Closed Circulatory System

Answer 27

Blood: Circulatory fluid confined to vessels
Heart(s) pump blood through branched vessels
Higher pressure- more efficient, requires more E
Annelids, cephalopods, vertebrates

Question 28

Components of Vertebrate Circulation

Answer 28

Cardiovascular system
Involves:
- Heart: Pumps blood
- Vessels: Carry blood
Exchange at capillaries

Question 29

What type of circulation do fish do?

Answer 29

Single circulation

Question 30

Single Circulation in Fish Cycle

Answer 30

Heart: 2 chambers
1 atrium
1 ventricle
Not very efficient

Blood enters the heart through the atrium and goes to the ventricle. Then moves up into the gill capillaries and then into body capillaries. Deoxygenated blood then returns to heart.

Question 31

What type of circulation do amphibians do?

Answer 31

Double Circulation

Question 32

Double Circulation in Amphibians Cycle

Answer 32

Heart: 3 chambers
2 atria
1 ventricle
Blood flow: 2 circuit

Deoxygenated blood goes into the right atrium which empties the blood into the ventricle. The ventricle pumps the blood into the skin and lung capillaries in the pulmocutaneous circuit. It picks up oxygen and returns it through the left atrium to the ventricle, then enters the systemic capillaries in the systemic circuit and then returns through the right atrium back to the ventricle.

Question 33

Double Circulation in Mammals & Birds

Answer 33

Heart: 4 chambers
2 atria
2 ventricles

Blood comes from body and goes into right atrium, goes through right atrioventricular valve into the right ventricle. It is pumped out of the right ventricle through the pulmonary valve into the pulmonary arteries which bring blood to the lungs which is the pulmonary circuit. Then the blood is brought back to the heart through the pulmonary veins. They dumps the blood into the left atrium and when the atria contract, the blood goes through the left atrioventricular value into the left ventricle and then when the ventricles contract the blood goes up through the aortic valve into the aorta which then goes to the systemic circuit which takes the blood through the rest of the body, dumps off the oxygen and the deoxygenated blood returns to the right atrium.

Question 34

Atria

Answer 34

Receive blood from veins

Question 35

Ventricles

Answer 35

Pump blood to arteries

Question 36

Pericardium

Answer 36

Connective tissue sac, encloses heart

Question 37

Atrioventricular valves

Answer 37

Flaps of connective tissue- prevent backflow
2 atrioventricular- right, left AV
Blood from tissues-> atria
Blood pressures in atria opens AV valves
Ventricular contractions closes AV valves

Question 38

Semilunar valves

Answer 38

Ventricles-> arteries
Opened by ventricular contraction
Pulmonary valve- RV-> pulmonary artery
Aortic valve- LV-> aorta

Question 39

Heart Contractions (Heartbeat)

Answer 39

Heartbeat starts by the SA node in the right atrium. Triggers the contraction of the right atrium. Intercalated discs allow the ions to directly diffuse from cell to cell which allows an action potential in one cell to directly depolarize the next cell. This allows the atria to contract in a coordinated way from top to bottom and then pause at the AV node between the right atrium and right ventricle. Pauses for 1/10th second to allow the blood to pump into the ventricle. The bundle branches transmit action potential to the apex of the heart and then radiate upwards through Purkinje fibers. The fibers contract the ventricles which push blood out through pulmonary arteries + aorta.

Question 40

Regulation of Heart Rate by NS

Answer 40

Baroreceptors: Sensory receptors, wall of blood vessels, heart
Detect changes in blood pressure
-> cardiac centers in medulla-> autonomic nerves-> SA node

Sympathetic- increase heart rate, strength of contraction
Parasympathetic- decrease HR

Question 41

Regulation of Heart Rate by Endocrine System

Answer 41

Stress
Adrenal medulla-> epinephrine-> increase heart rate

Temperature
Increase temp impresses heart rate (fever-> faster pulse)
Decrease temp decrease HR

Question 42

3 components of blood vessel structure

Answer 42

3 layers
Endothelium- lines lumen- smooth
Smooth muscle- Thicker in arteries, thin in veins
Connective tissue- Many elastic, collagen fibers
Thick walls prevent diffusion

Question 43

Arteries

Answer 43

Heart-> organs
Arteries-> arterioles in organs-> capillaries

Question 44

Capillaries

Answer 44

Microscopic blood vessels in tissues
Capillary bed: Network of capillaries, infiltrate all tissues
Exchange between blood, tissues

Question 45

Capillary Structure

Answer 45

2 layers- endothelium and basal lamina
At least 1 capillary near every cell in body
Only location of exchange between blood and interstitial fluid

Question 46

Veins

Answer 46

Organs-> heart
Capillaries-> venues-> veins

Between skeletal muscle- squeezed by muscles
1-way valves prevent backflow

Question 47

Veins vs. Arteries

Answer 47

Direction of blood flow-> veins bring blood to heart, arteries take blood from heart

Question 48

Mechanism of Exchange

Answer 48

Thin capillary lining- single cell layer
Allows diffusion of nutrients, ions, gases, waste

Plasma under pressure
-> some forced into tissue-> interstitial fluid

Question 49

Interstitial Fluid

Answer 49

No RBCs
25% of protein content of blood- hypotonic relative to blood
Leads to…
Fluid exchange between capillaries, tissues- in and out
Antagonistic forces- blood pressure, osmotic pressure
Arterial end of capillaries- fluid out
Venous end of capillaries- fluid in

Not all fluid returns
15% remains in interstitial fluid- intolerable over long term

Question 50

Lymphatic System

Answer 50

Accessory circulatory system
Plasma of blood into the interstitial fluid into the lymphatic system and circulates back into the blood vessels
Absorbs lipids from SI
Defend against disease

Question 51

Anatomy of lymphatic system

Answer 51

Contains lymph: watery fluid derived from interstitial fluid
Travels through lymph vessels
Lymph nodes- where vessels meet
Return to circulatory system via lymph ducts
Flows due to muscle contractions