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Biology 102 > Lecture 10 - Circulation > Flashcards

Lecture 10 - Circulation Flashcards

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1
Q

Components of the Circulatory System

A
  • Heart: muscular pump
  • Blood: fluid that can transport things around the body
  • Blood vessels: conduits through which the fluid can be pumped around the body
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2
Q

Purpose of the Circulatory System

A

Pump nutriients, respiratory gases, wastes, hormones

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3
Q

Atrium

A
  • region of the heart that receives incoming blood

* A = first

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4
Q

Ventricle

A

Region of the heart that pumps outgoing blood

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5
Q

Arteries

A
  • Carry blood away from the heart
  • branch out into arterioles

A=away

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6
Q

Veins

A
  • Carry blood back to the heart
  • smaller vessels (venules) join together to form larger vessels
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7
Q

Capillaries

A
  • where arteries (arterioles) and veins (veinules) meet
  • thiny, thin walled
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8
Q

Fish Circulatory System

A
  • 2 chambered heart
  • blood is pumped in a single circuit

heart–> gills–> tissue of the body –> heart

Process:

  1. Atrium receives blood from the body
  2. pumps it into the more muscular ventricle
  3. ventricle pumps blood to gills (gas exhange)
  4. blood elaving gills colelcts in large artery
  5. distributes blood to smaller arteries leading to tissues and organs of the body
  6. in tissues blood flows through beds of capilllaries
  7. blood collects in veins
  8. returns to atrium of heart
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9
Q

What is the disadvantage of fish circulation?

A
  • blood loses pressure as it travels through gills
  • limits ability to supply tissues with nutrients, oxygen
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10
Q

Why do birds/mammals have a different system of circulation?

A
  • high nutrient demands and thus a very high density of vlood vessels
  • heart must generate a high blood pressure to perfuse all the vessels
  • have developed two separate circuits for blood flow
    1. pulmonary (heart–> lungs –> heart)
    2. systemic (heart –> tissues –> heart)

oxygenated blood can be pumped out of the heart to tissues at hihg pressure

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11
Q

Features Separate Pulmonary and Systemic Curcuits

A
  • 4 chambered hearts
  • Two Circuits:
    1. Pumlonary
    2. Systemic
  • Oxygenated and deoxygenated blood cannot mix
  • Systemic receives blood with highest oxygen content
  • blood with lowest oxygen content and highest CO2 is sent to lungs
  • Can operate at different pressures
  • large/higher pressure to pump blood through vessels of systemic
  • lower pressure needed for pulmonary circuit in lungs
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12
Q

Comaprison of Pressure in Systemic and Pulmonary Circuit

A
  • systemic: large pressure needed for pumping blood thruogh all the vessels (longer distance)
  • pulmonary: lower pressure (shorter distance)
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13
Q

Features of the Human Heart

A
  • Right atrium: receives deoxygenated blood from systemic circuit
  • right ventricle: pumps deoxygenated blood through pumlonary circuit to get deoxygenated
  • left atrium: receives oxygenated blood from the pulmonary circuit
  • left ventricle: pumps oxygenated blood through the systemic circuit to get delivered to tissues

* one way valves prevent back flow

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14
Q

Right Heart vs Left Heart

A
  • right heart receives deoxygenated blood (blue) and pumps it to lungs
  • left heart receives oxygenated blood (red) and pumps it to the body
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15
Q

Path of Blood flow INTO the heart (right side)

A
  1. right atrium receives deoxygenated blood from superior and inferior vena cava
  2. Blood flows through an atrioventricular (av) valve into the right ventricle
  3. filling of the ventricle results from passive flow while the heart is relaxed between beats
  4. at the end of filling, the right atrium contracts
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16
Q

Where does the heart recieve blood from?

A
  • superior and inferior vena cava
  • into the av valve
17
Q

How blood is pumped to lungs (2)

A
  1. right atrium contracts, right ventricle contracts
  2. AV valve closes
  3. Blood is pumped into the pulmonary artery leading to lungs (through pulmonary valve)
  4. gas exchange occurs in the lungs
  5. oxygenated blood returns to heart via the pulmonary veins
18
Q

How blood flows in heart after beind oxygenated in lungs (3)

A
  1. re-enters heart in left atrium
  2. blood enters left ventricle through another AV valve
  3. ventricular filling is passive, completed with the atria contract
  4. left ventricle (very powerful), contracts
  5. pushes open aortic valve
  6. blood rushes into aorta to begin circulation throughout the body
19
Q

The Cardiac Cycle

A

* both sides of the heart contract at the same time

  1. relaxation
  2. contraction of the two atria
  3. contraction of the two ventricles

Two phases:

  • diastole:
  • ventricles relax
  • at very end, atria contract
  • systole:
  • ventricles contract
20
Q

What are the sounds of the heart beat?

A
  • as ventricles begin to contract, AV valves close
  • “lub”
  • transition from diastole to systole
  • as ventricule begin to relax, aortic and pulmonary valves close
  • “dup”
  • transition from systole to diastole
21
Q

What is a heart murmer

A
  • when valves do not close completely, there is a backwards flow of blood
  • “whoosh”
22
Q

What is your pulse?

A
  • pressure wave created by the contraction of the left ventricle in systole
23
Q

Properties of Cardiac Muscle Cells

A
  • has electrical signaling properties (like a neuron)
  • can fire action potentials
  • cardiac muscle cells are directly connected to each other via gap junctions
  • cytoplasms are connected so direct and rapid spread of electrical signal
  • coordinated contraction
24
Q

How do cardiac cells communicate?

A
  • gap junctions
  • dont use neurotransmitters
25
Q

Pacemaker cells

A
  • cardiac muscle cells that can initiate action potentials without stimulation from the nervous system
  • fire action potentials and stimulate neighboring cells to contract
  • Sinoatrial (SA) node is the primary pacemake of the heart
26
Q

Sinoatrial Node

A

Primary pacemake of the heart

in right atria

27
Q

Properties of the pacemaker

A
  1. slower to rise
  2. broader
  3. slower to return to resting potentia
28
Q

Process of Pacemaker

A
  1. RESTING
  • specialized Na+ channels are open
  • open at hyperpolarized voltage
  • resting potential is less negative
  1. RISING
  • voltage gated Ca++ channels open –> ca++ influx
  • open and close more slowly than voltage gated Na+ channels = broader shape
  1. FALLING: same as usual

*hyperpolarization then causes the Na+ channels to open and AP start again

  • voltage gated K+ chanels open
29
Q

Nervous System and Heart Beat

A
  • rate of heart beat can be controlled by nervous system
  • regulates rate at which the resting potential dirfts upwards toward threshold
  • some neurotransmitters can stimulate depolarization
  • resting potential reached more quickly
  • interval between pacemaker AP is decresed
  • heart beats faster
  • some neurotransmitters stimulate hyperpolarization
  • membrane potential rises even more slowly
  • interval between pacemaker action potentials lengthen
  • heart slows down
30
Q

Process of pacemaker and atrial contraction

A
  1. heart beat begins with AP in sinoatrial node
  2. action potential spreads rapidly through electrically coupled cells of the atria
  3. there ar no gap junctions between the cells of the atria and the cells of the ventricles

* ventricles do not contrac tin unison with the atria

31
Q

atrioventricular (AV) node

A
  • at junction of atria and ventricles
  • specialized cardiac cells
  • stimulated by depolarization of the atria
32
Q

Ventricular Contraction

A
  1. AV node generatea AP
  2. conducted to ventricles via “bundle of his”
33
Q

Bundle of His

A
  • modified muscle fibers that conduct signal but do not contract
  • branches out across ventricles as Purkinje fibers
  • ensure that cardiac action potential spreads rapidly and evenly
  • muscle cells of the ventricles experience AP and contract
34
Q

Unique Properties of Cardiac Muscle Cells

A
  1. very long depolarization phase
    * allows for prolonged muscle contraction
  2. rising phase
    * is due to Na+ channels like a normal AP
  3. Falling
  • Voltage gated Ca++ channels open
  • allows for extended plateau of depolarization
  • Ca++ allows muscle cells to contract
  • falling phase is due to K+ channels like normal AP
35
Q

Summary of Contraction Patterns

A
  • right and left atria contract at the same time
  • coordinated by gap junctions
  • the right ventricle and the elft ventricle contract at essentially the same time
  • coordinated by bundle of his, purkinjie fibers, gap junctions
  • Atria and ventricles contract at different times
  • signal originates in sinoatrial node (atria) and spreads to AV node (ventricles)
36
Q

What coordinates the atria to contract?

A

gap junctions

37
Q

What coordinates the right and left ventricles to contract?

A
  • bundle of his, purkinjie fibers, gap junctions
38
Q

ECG/EKG

A

Electrocardiogram

Electrical events int he cardiac muscle can be recorded by electrodes on the surface of the body

39
Q

Features of EKG

A

P=depolarization of the atrial muscle

  • atrial contraction
  • end of diastole

Q-S= depolarization fo ventricles

  • ventricle contraction
  • blood pumped out
  • systole
  • start AV valves close
  • lub)

T= relaxation and repolarizatoin of ventricles

  • start of diastole
  • aortic and pulmonary valves close
  • “dub”

Biology 102 (15 decks)

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