Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biology Option D > Option D.4 The Heart > Flashcards

Option D.4 The Heart Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

How skeletal and cardiac muscles similar?

A
  • surrounded and enclosed by SARCOLEMMA, a membrane
  • transverse tubules tunnel in and around sarcomeres
  • fluid filled system of branching membranous sacs, cardiac has SARCOPLASMIC RETICULUM, skeletal have ENDOPLASMIC RETICULUM
  • cardiac are striated in appearance; have similar arrangement of actin and myosin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How are cardiac and skeletal muscles different from one another?

A

cardiac muscles are:

  • shorter /wider than skeletal
  • single nucleus, not coenocytic (skeletal)
  • branched and joined by intercalated discs in complex (3D) network allows contraction in 3D
  • supplied by mitochondria (make up larger volume)
  • contract even without stimulation of nerve/not voluntarily controlled
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are intercalated discs?

A

cardiac muscle cells remain single cells by being interconnected by intercalated discs (are between junctions of cells);
contain gap junctions (openings) for cytoplasm to pass;

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the benefit of having cardiac cell have gap junctions?

A

freely sharing cytoplasm allows cardiac muscles to send signals quickly; synchronizing contractions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Is the interconnected system of cardiac muscle fibres separate from other ventricle?

A

Yes. Network of atria walls is entirely separate from ventricles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the effect of having cardiac muscle fibres separate from ventricles?

A

ensures transmission delay of electrical between atria and ventricle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What stages is a heartbeat divided into?

A

systole and diastole

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What happens during the systole stage (in heart)?

A

heart muscles contracts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What happens during the diastole stage (in heart)?

A

heart muscle relaxes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Why do we say the heart is myogenic in origin?

A

inherit electrical activity triggers continuous beating of heart by network of specialized self-excitable cardiac muscle fibre

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are autorhythmic cells?

A

specialized, self-excitable cardiac muscle fibres

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Where are the autorhythmic cells located?

A

right atrial wall, close to the points where the vena cavae empty into the heart

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the network of cardiac muscles fibres?

A

Sinoatrial (SA) node

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How does the atrial systole occur?

A

electrical charge runs through network of muscle fibres (in wall of atria) via gap junctions (intercalated discs);
atrial walls contract

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Do signals fro SAN pass directly to ventricles?

A

No; muscle fibres from atria and ventricles are separate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What feature of the heart ensures the delays of the SAN being passed along?

A

coronary muscle fibres from atria and ventricles being completely separat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

If signals from SAN cannot directly pass on to ventricles, how are they passed on?

A

stimulus picked up by AV node (at base of right atrium)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Why is there a delay between arrival and passing on the stimulus at the AV node?

A
  • cells of the AV node taking longer to become excited
  • diameter of AV node cells are smaller, slows down conduction
  • fewer sodium ion channels in AV node cells (more negative resting potential)
  • fewer gap junctions in the intercalated discs (between cells)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What does the delay in conduction allow?

A

time for atrial systole before the AV vales close; atria contracts and empty blood into ventricular before ventricles contract;
prevents both to contract simultaniously

20
Q

What do AV bundle do?

A

conduct signal into ventricles to the point, where signal split into left and right branch (2 ventricles)

21
Q

What are Purkinje fibres?

A

conducting fibres that deliver signal to base of each ventricle, and coordinate contractions starting from base

22
Q

What is ventricular systole?

A

Conducting fibres coordinate contraction of entire ventricle walls, starting at the base of heart upwards

23
Q

Why is conduction during ventricular systole fast?

A

fibres:

  • are less in number
  • have larger diameter
  • numerous voltage-gated sodium ion channels
  • are well supplied with mitochondria and have glycogen store - reserves of respiratory substrate, in effect
24
Q

What happens after every contraction of the heart?

A
  • period of insensitivity to stimulation, the REFRACTORY PERIOD ( enforced diastole)
  • blood passively refills (takes more time)
25
Q

How do signals from the SA node cause initial contraction in atria?

A
  • SA node initiate action potential without stimulation
  • initiation occurs rhythmically
  • pacemaker of heart
  • gap junctions allow electric charges to flow feely between cells
  • SA node spreads across atrium
  • atria undergo systole/contraction
26
Q

What occurs after atria systole?

A
  • signals from SA reaches after delay of passing on stimulus AV node
  • delay allows time for atrial systole
  • AV bundles receive signal from AV node;
  • signal rapidly split between bundle branches;
  • at apex of heart, bundle connects to Purkinje fibres
  • signals spread more rapidly throughout heart via Purkinje;
  • ventricles must undergo systole
  • contraction of ventricles starts at apex
27
Q

What happens if the SA node is damaged/diseased?

A

normal heart rhythm restored by implantation of artificial pacemaker;
delivers electrical impulse via electrodes to heart wall;

28
Q

When does a patient get assigned a pacemaker?

A
  • heart with slow heartbeat;
  • conducting fibres are faulty;
  • can also only be used when normal heart beat missing
29
Q

What are the causes of the sound of the heartbeat?

A 
two sounds ( lub and dub) caused by closing of AV vales first;
then closing of semi lunar valves soon after
30
Q

Why was there a pressure to invent the stethoscope?

A
  • patients too obese so sounds cant be heard
  • patients with vermin couldnt be washed
  • women couldnt be undressed
    for doctors to pout ear to chest
31
Q

What is hypertension?

A

persistent high blood pressure. Systole pressure greater than 140

32
Q

What are causes of hypertension?

A

deposition of fat in arteries and formation of fibrous tissues there, impending blood flow ;
thickening of artery wall causes loss of elasticity;
high salt in diet causes more retention in body;
smoking, nicotine temporarily elevates blood pressure;
obesity/no exercise;
excessive alcohol

33
Q

What are consequences of hypertension?

A

damages heart, blood vessels, brain and kidneys without noticeable discomfort;
atherosclerosis;
increased workload on heart makes brain hemorrhage more likely

34
Q

What is thrombus?

A

blood clot forming within blood vessel known as thrombus

35
Q

What is embolus?

A

blood clot after it breaks from blood vessel and circulates in bloodstream

36
Q

How is thrombosis caused?

A

caused by atherosclerosis (degeneration of artery walls)

  1. damage to artery walls - strands of yellow fat deposited under endothelium; builds from LDLs circulating in blood
  2. raised blood pressure - fatty deposits and formation of fibrous tissues impede blood flow
  3. lesion formation/inflammatory response at fat deposit - smooth lining of artery breaks down; blood exposed to fatty deposits; cholesterol accumulates; smooth muscle /collages fibres profilerate plaque; platelets are collected and release trigger for inflammatory response; forms thrombus
37
Q

What are lesions?

A

atherosclerosis plaque

38
Q

What are consequences of thrombosis?

A
  • heart attack: embolus released into coronary artery; blood supply to tissue is blocked; tissues deprived of oxygen; tissues die; muscle of LV wall very vulnerable; heart ceases to effectively pump; arteries can be surgically by passed
  • stroke: when embolus blocks artery to brain; neurons depend on supply of oxygen and glucose; no blood supply causes neurons to die; cannot be replaced
39
Q

Conditions of Abnormal Traces on ECG

A

Recognize tachycardia, ventricular fibrillation, heart block

40
Q

What is Arrhythmia?

A

condition of irregularity in heart due to defect conduction system due to:

  • drugs (alcohol, nicotine)
  • anxiety, potassium deficient
41
Q

What is ventricular fibrillation?

A

not synchronized contraction of ventricle causes heart failure (not enough blood pumped); some muscle fibres contraction some contracting

42
Q

what is Tachycardia?

A

heart rate over 100 beats per minute; relatively harmless but can be life threatening

43
Q

What is heart block?

A

obstruction of electrical impulse is AV node

44
Q

What is defibrillation?

A

life threatening cardiac conditions can be treated using this;
delivers therapeutic dose of electrical energy to heart using defibrillator;
ends faulty rhythmical electrical activity/re-establishes normal pacemaker

45
Q

What are AEDs?

A

automated external defibrillators; can be used by anyone (easy to handle/audible instructions); defibrillator detects heartbeat itself for person to administer correct electric shock

Biology Option D (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions