Lecture 25- Circulation Flashcards

(51 cards)

1
Q

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

A

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

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2
Q

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

A

Artery

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3
Q

The initiation of a heartbeat occurs at the _____.

A

Sinoatrial (SA) node

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4
Q

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

A

Atria

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5
Q

How can the endocrine system influence heart rate?

A

Secretion of epinephrine during acute stress accelerates heart rate
Also temperature

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6
Q

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

A

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

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7
Q

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

A

Purkinje fibers

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8
Q

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

A

Ventricles

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9
Q

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

A

Endothelium → Smooth muscle → Connective tissue

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10
Q

The aortic and pulmonary valves are types of _____.

A

Semilunar valves

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11
Q

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

A

Pericardium

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12
Q

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

A

Sustain higher pressures

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13
Q

How many chambers do fish hearts have?

A

Two

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14
Q

What is the connective tissue surrounding blood vessels composed of?

A

Collagen fibers

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15
Q

True or False: Amphibians withdraw oxygen through their skin.

A

TRUE

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16
Q

____ is the body fluid between blood vessels and cells.

A

Interstitial fluid

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17
Q

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

A

Atrioventricular (AV) node

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18
Q

What are the primary functions of the lymphatic system?

A

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

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19
Q

What is lymph composed of?

A

Derived from interstitial fluid

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20
Q

What are baroreceptors and what is their primary function?

A

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

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21
Q

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

A

Pulmonary veins

22
Q

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

A

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

23
Q

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

A

Bundle branches

24
Q

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

25
True or False: Resting heart rate during a fever is generally slower than a healthy individual.
False; resting heart rate during a fever is generally FASTER than a healthy individual
26
Open Circulatory System
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
27
Closed Circulatory System
Blood: Circulatory fluid confined to vessels Heart(s) pump blood through branched vessels Higher pressure- more efficient, requires more E Annelids, cephalopods, vertebrates
28
Components of Vertebrate Circulation
Cardiovascular system Involves: - Heart: Pumps blood - Vessels: Carry blood Exchange at capillaries
29
What type of circulation do fish do?
Single circulation
30
Single Circulation in Fish Cycle
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.
31
What type of circulation do amphibians do?
Double Circulation
32
Double Circulation in Amphibians Cycle
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.
33
Double Circulation in Mammals & Birds
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.
34
Atria
Receive blood from veins
35
Ventricles
Pump blood to arteries
36
Pericardium
Connective tissue sac, encloses heart
37
Atrioventricular valves
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
38
Semilunar valves
Ventricles-> arteries Opened by ventricular contraction Pulmonary valve- RV-> pulmonary artery Aortic valve- LV-> aorta
39
Heart Contractions (Heartbeat)
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.
40
Regulation of Heart Rate by NS
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
41
Regulation of Heart Rate by Endocrine System
Stress Adrenal medulla-> epinephrine-> increase heart rate Temperature Increase temp impresses heart rate (fever-> faster pulse) Decrease temp decrease HR
42
3 components of blood vessel structure
3 layers Endothelium- lines lumen- smooth Smooth muscle- Thicker in arteries, thin in veins Connective tissue- Many elastic, collagen fibers Thick walls prevent diffusion
43
Arteries
Heart-> organs Arteries-> arterioles in organs-> capillaries
44
Capillaries
Microscopic blood vessels in tissues Capillary bed: Network of capillaries, infiltrate all tissues Exchange between blood, tissues
45
Capillary Structure
2 layers- endothelium and basal lamina At least 1 capillary near every cell in body Only location of exchange between blood and interstitial fluid
46
Veins
Organs-> heart Capillaries-> venues-> veins Between skeletal muscle- squeezed by muscles 1-way valves prevent backflow
47
Veins vs. Arteries
Direction of blood flow-> veins bring blood to heart, arteries take blood from heart
48
Mechanism of Exchange
Thin capillary lining- single cell layer Allows diffusion of nutrients, ions, gases, waste Plasma under pressure -> some forced into tissue-> interstitial fluid
49
Interstitial Fluid
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
50
Lymphatic System
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
51
Anatomy of lymphatic system
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