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heart test Flashcards

1
Q

DOUBLE CIRCULATION AND HEART STRUCTURE

A
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2
Q

B3.2.15: Adaption of the mammalian heart for delivering pressurized blood to the arteries.
- Label a diagram of the heart with the following structure names: superior vena cava, inferior vena cava, pulmonary semilunar valve, aorta, pulmonary artery, pulmonary veins, aortic semilunar valve, left atrioventricular valve, left ventricle, septum, right ventricle, left atrium, right atrium and right atrioventricular valve.

A

keep practicing: https://dochub.com/tamilore-oyebode-ddunmo/xP5LzojKa8EjN88R7ZDlO3/circulatory-system-and-parts-of-the-heart

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3
Q

functions of aorta, pulmonary arteries, coronary arteries, vena cava, pulmonary veins, CARDIAC veins

A
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4
Q

TYPES OF VALVES - FUNCTION

A

pocket valves/AV valves/Valves prevent backflow of blood and keep the blood moving in one direction through the heart.

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5
Q

B3.2.14: Differences between the single circulation of the bony fish and the double circulation of mammals.
- Draw a diagram to illustrate the double circulation system in mammals.
- Identify and describe the differences between the single circulation of the bony fish and the double circulation of mammals.

A

fish - single loop circulatory system where blood passes through the heart once per circuit/two-chambered - blood is oxygenated through the gills before being pumped to the rest of the body
mammals - double-loop circulatory system where blood passes through the heart TWICE per circuit/four-chambered - separation of oxygenated and deoxygenated blood, leading to efficient transport of oxygen to tissues, with a high metabolic rate and the ability to regulate body temperature.

  • both are closed circulation systems

note:
Pulmonary circulation → to and from the lungs
Systemic circulation → to and from all other organs, including the heart muscle

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6
Q

The pericardial membrane surrounds the heart and consists of…

A

epicardium (shared by the heart wall and pericardial membrane), myocardium, and pericardium (& the pericardial cavity)

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7
Q

Adaptations of cardiac muscle cells and striated muscle fibres.
- Compare cardiac muscle tissue to skeletal muscle tissue.

A
  • Skeletal muscles: long and narrow, multinucleated, voluntary control
  • Cardiac muscles: short and wide, one nucleus, involuntary control
  • Both have striated appearances & similar arrangements of actin and myosin
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8
Q
  • Describe how the Y-shape (branched), intercalated discs and gap junctions of cardiac muscle cells allow for propagation of the stimulus to contract.
A
  • Cardiac muscle cells contract without stimulation by the central nervous system (contraction is myogenic - originating in heart muscle cells themselves, as in the generation of the of the heartbeat)
  • Cardiac muscle cells are branched, allowing for faster signal propagation and contraction in three dimensions
  • Cardiac muscles cells are not fused together, but are held together by intercalated discs. They allow for easy transfer of electrical impulses between cells.
  • Cardiac muscle cells have more mitochondria, as they are more reliant on aerobic respiration than skeletal muscle

RECALL: GAP JUNCTIONS ALLOW FOR SUBSTANCES TO QUICKLY PASS BETWEEN CELLS (forms a channel between adjacent cardiac muscles)

  • Cardiac muscle has a longer period of contraction and refraction, which is needed to maintain a viable heartbeat
    The heart tissue does not become fatigued (unlike skeletal muscle), allowing for continuous, life long contractions
    The interconnected network of cells is separated between atria and ventricles, allowing them to contract separately
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9
Q

ARTERIES, VEINS, AND CAPILLARIES

A
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10
Q

B3.2.1: Adaptations of capillaries for exchange of materials between blood and the internal or external environment.
- Describe how the structures of capillaries are adapted to capillary function. Include lumen diameter (SA:V), branching, wall thickness, and fenestrations (pores).

A
  • Blood travels slowly under low pressure allowing more opportunity for exchange. (B/C IT’S BRANCHED)
  • Wall is one cell thick allows easy diffusion of substances in and out of the capillary due to the short diffusion distance.
  • Basement membrane is permeable to many substances
  • Due the the massive number of capillaries present and the small lumen, the surface area available for the exchange of substances is very large.
  • The walls and membrane can contain pores to further aid the diffusion of substances
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11
Q

B3.2.1: Adaptations of capillaries for exchange of materials between blood and the internal or external environment.

  • know tissue fluid and fenestrated capillaries here for exam
  • tissue fluid leaks out of basement membrane
A

NEXT SLIDE:
The capillary wall consists of one layer of endothelial cells. This layer of cells has a coating of extracellular ficours proteins which are crosslinked to form a gel. The gel is called the basement membrane and it acts as a filter that allows small or medium-sized particles to pass through, but NOT macromolecules. These are pored between the epithelium cells, so capillary wall is extremely permeable. The pores allow part of the blood plasma, but NOT the red blood cells, to leak out the basement membrane.
The fluid that leaks out is very similar but not identical in composition to blood plasma. It is called tissue fluid. Tissue fluid contains oxygen, glucose and all other substances in blood plasma except large protein molecules, which are too large to pass through the basement membrane.

-The fluid flows between the cells in a tissue, allowing the to absorb useful substances and excrete waste products. The tissue fluid then re-enters the capillary network.
In some tissues, there are greater numbers of very large pores in the capillary walls. These are fenestrated capillaries - allow larger volume of tissue fluid to be produced, which speeds up exchange between the tissue cells and the blood.

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12
Q

B3.2.2: Structure of Arteries and veins.
- Compare the diameter, relative wall thickness, lumen size, number of wall layers, abundance of muscle and elastic fibers and presence of valves in arteries and veins.
- Given a micrograph, identify a blood vessel as an artery, capillary or vein.

A

Diameter: both larger than 10 micrometers
Wall thickness: arteries are very thick and small lumen/veins are very thin and large lumen
Number of layers: both have the same 3
Muscle and elastic fibers in wall: arteries - abundant/veins - small amounts
Valves: arteries - none/veins - present in many

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13
Q

B3.2.3 Adaptations of arteries for the transport of blood away from the heart.
- State the function of arteries.

A

CARRIES HIGH PRESSURE BLOOD AWAY FROM THE HEART TO THE TISSUES THAT NEED IT (BIGGER THAN 10 MICROMETERS)

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14
Q
  • Describe the structures and functions of the three layers of the artery wall.
A

Tunica Intima:
- The innermost layer of the artery wall.
- Comprised of endothelial cells, which form a smooth, friction-reducing surface for blood flow.
- Also contains a layer of connective tissue called the subendothelial layer, which provides structural support.
- Functions include regulating vascular tone, preventing blood clot formation, and facilitating the exchange of nutrients and waste products between blood and surrounding tissues.

Tunica Media:
- The middle layer of the artery wall.
- Composed primarily of smooth muscle cells embedded in a matrix of elastic fibers and collagen.
- Smooth muscle cells in this layer allow for vasoconstriction (narrowing of the vessel) and vasodilation (widening of the vessel), thereby regulating blood pressure and blood flow.
- Elastic fibers provide resilience and recoil properties, allowing arteries to stretch and recoil in response to changes in blood pressure.
- Collagen fibers provide structural support and strength to the vessel wall.

Tunica Externa:
- The outermost layer of the artery wall.
- Consists mainly of connective tissue, primarily collagen fibers and some elastic fibers.
- Functions to anchor the artery to surrounding structures, such as other blood vessels, organs, and tissues.
- Provides structural support and protection for the artery.
- Also contains nerves, blood vessels (vasa vasorum) that supply the arterial wall with oxygen and nutrients, and lymphatic vessels.

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15
Q
  • Discuss how the wall thickness (COLLAGEN), lumen size, and muscle and elastic allow arteries to withstand and maintain high blood pressures.

NEGATIVE: IF THE PRESSURE IS TOO HIGH, IT CAN MAKE YOUR ARTERIES LESS ELASTIC, REDUCING BLOOD FLOW

A

Muscle contracts to decrease the size of the lumen. This causes an increase blood pressure and therefore maintains high blood pressure between the pulses of high pressure blood travelling from the heart.

Elastic fibres stretch to increase the lumen with each pulse of blood. After the pulse of blood passes the fibres recoil decreasing the lumen size and therefore helping to maintain a high blood pressure. Elastic fibres make up as much as 50% of the dry mass of the artery walls. Collagen fibres are tough rope-like proteins with high tensile strength - withstand high and variable blood pressures to prevent aneurysms.

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16
Q

B3.2.4: Measurement of pulse rates
- State the unit of measurement of the pulse rate.
- Outline two methods for determining heart rate.

A
  • Pulse rate is the number of times a person’s heart beats per minute.
  • UNITS: BPM
  • Using two fingers (typically the index and middle fingers) to press lightly on the pulse point.
  • Count the number of beats felt in a specific time frame, usually 15 or 30 seconds, then multiply to find the beats per minute (bpm).
  • FITNESS BANDS
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17
Q

B3.2.5: Adaptation of veins for return of blood to the heart.
- State the function of veins.
- Discuss how pocket valves, thin walls (CAN HOLD A LARGE VOLUME OF BLOOD) and skeletal muscles maintain the flow of blood through a vein.

NEGATIVE: LITERALLY 80% OF YOUR BODY’S BLOOD IS RESTING IN YOUR VEINS, NOT MOVING/VALVES STOP WORKING…UH OH (venous disease)

A
  • CARRY LOW PRESSURE BLOOD BACK TO THE HEART USING VALVES TO ENSURE BLOOD FLOWS IN THE CORRECT DIRECTON
  • Veins return blood to the heart for re-circulation. The flow is irregular. Around 80% of the blood in a person is at rest in the veins, but this is reduced during vigorous activity.
  • The large lumen (compared to arteries and the thickness of the wall) means that the blood is under low pressure.
  • Because there is less pressure to resist the walls of the veins are thinner, less elastic, less muscle than the arteries.
  • Veins typically pass between skeletal muscle groups, which facilitate venous blood flow via periodic skeletal contractions.
    Veins typically run parallel to arteries, and a similar effect can be caused by the rhythmic arterial bulge created by a pulse.
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18
Q

FOR CARDIAC CYCLE REVIEW, REFER BACK TO ORIGINAL FLASHCARDS!!! (BELOW IS A MIX OF CARDIAC CYCLE AND HEARTBEAT)

A
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19
Q

B3.2.16: Stages in the cardiac cycle.
Define myogenic contraction.

A

A contraction initiated in the muscle itself and not dependent on neural stimulation

20
Q

Define cardiac cycle.

A

The cardiac cycle describes the series of events that take place in the heart over the duration of a single heartbeat. The heart beasts at an approximate rate of 60-100 times per minute, so each cardiac cycle is about 0.8 seconds long.
- It is comprised of a period of contraction (systole) and relaxation (diastole).

21
Q

Explain the flow of blood during atrial and ventricular systole and diastole.

A
  • Blood returning to the heart will flow into the atria and ventricles as the pressure in them is lower (due to low volume of blood)
    When ventricles are ~70% full, atria will contract (atrial systole), increasing pressure in the atria and forcing blood into ventricles
    As ventricles contract, ventricular pressure exceeds atrial pressure and AV valves close to prevent backflow (first heart sound)
    With both sets of heart valves closed, pressure rapidly builds in the contracting ventricles (isovolumetric contraction)
    When ventricular pressure exceeds blood pressure in the aorta, the aortic valve opens and blood is released into the aorta

DIASTOLE:
As blood exits the ventricle and travels down the aorta, ventricular pressure falls
When ventricular pressure drops below aortic pressure, the aortic valve closes to prevent backflow (second heart sound)
When the ventricular pressure drops below the atrial pressure, the AV valve opens and blood can flow from atria to ventricle
Throughout the cycle, aortic pressure remains quite high as muscle and elastic fibres in the artery wall maintain blood pressure

22
Q

Define systolic and diastolic blood pressure.
State the cause of systolic and diastolic blood pressure.
Interpret systolic and diastolic blood pressure measurements from data and graphs.

A
23
Q

HEART BEAT (see OG flashcards for more review)

A
24
Q

B3.2.15 & B3.2.16: Adaptations of mammalian heart for delivering pressured blood to the arteries. Stages in the cardiac cycle.
- Outline the role of (PACEMAKER) cells in the sinoatrial node.
- State the reason why the sinoatrial node is often called the pacemaker.

ADDED SIDE NOTE ABOUT CARDIAC CONTRACTION

A
  • Within the wall of the right atrium are a specialized cluster of cardiomyocytes which direct the contraction of heart muscle tissue. This cluster of cells are collectively called the sinoatrial node (SA node or SAN)
  • The sinoatrial node acts as the primary pacemaker – controlling the rate at which the heart beats (i.e. pace ‘making’)
    The SA node triggers roughly 60 – 100 cardiac contractions per minute (normal sinus rhythm)

SIDE NOTE:
Cardiac muscle cells are not fused together but are instead connected via gap junctions at intercalated discs
This means that while electrical signals can pass between cells, each cell is capable of independent contraction
The coordinated contraction of cardiac muscle cells is controlled by specialized autorhythmic cells (‘pace makers’)

25
Q
  • Describe the propagation of the electrical signal from the sinoatrial node through the atria and ventricles.
  • Describe the motion of the signal to contract from the AV node through the ventricles.
  • State that the contraction of the ventricle begins at the heart apex.
A
  • The sinoatrial node sends out an electrical impulse that stimulates contraction of the myocardium (heart muscle tissue)
  • This impulse directly causes the atria to contract and stimulates another node at the junction between the atrium and ventricle
  • This second node – the atrioventricular node (AV node) – sends signals down the septum via a nerve bundle (Bundle of His)
  • The Bundle of His innervates nerve fibres (Purkinje fibres) in the ventricular wall, causing ventricular contraction
26
Q
  • Outline the causes of the delayed initiation of contraction of ventricles.
  • State the function of a delayed contraction of the ventricle.
A
  • The AV node propagates electrical signals more slowly than the SA node, creating a delay in the passing on of the signal/SMALLER DIAMETER TOO/FEWER GAP JUNCTIONS
  • This delay allows time for the ventricles to fill with blood following atrial contractions so as to maximize blood flow
27
Q
  • Outline the role of the atrioventricular node in the cardiac cycle.
A
  • separates atrial and ventricular contractions/sending electrical signals down septum
28
Q
  • Explain the events of the cardiac cycle, including atrial and ventricular systole and diastole and the movement of the signal to contract through the heart.
A
  • SA NODE sends out electrical signals which are propagated throughout the entire atria via gap junctions in the intercalated discs. In response, the cardiac muscle within the atrial walls contract simultaneously (atrial systole)
  • Ventricular contraction occurs following excitation of the atrioventricular node (located at the atrial and ventricular junction). The AV node sends signals down the septum via a nerve bundle (Bundle of His)
    The Bundle of His innervates nerve fibres (Purkinje fibres) in the ventricular wall, causing ventricular contraction. This sequence of events ensures contractions begin at the apex (bottom), forcing blood up towards the arteries

Heart Relaxation / Diastole
- After every contraction of the heart, there is a period of insensitivity to stimulation (i.e. a refractory period)
- This recovery period (diastole) is relatively long, and allows the heart to passively refill with blood between beats
- This long recovery period also helps prevent heart tissue becoming fatigued, allowing contractions to continue for life

29
Q

C3.1.11: Modulation of sleep patterns by melatonin secretion as a part of cardiac rhythms.
- Define circadian rhythm. (pmb)
- Describe the secretion and action of melatonin.

A
  • Circadian rhythm = the physical, mental, and behavioral changes an organism experiences over a 24-hour cycle.
  • Melatonin levels generally begin to rise in the mid to late evening, remaining high for most of the night, and then drop in the early morning hours. Light from the sun can also affect how much melatonin your body produces (seasonal depression). Natural melatonin levels slowly drop with age.
  • melatonin makes you sleepy, drops core body temp., reduces kidney production of urine
30
Q
  • Outline the mechanism that regulates melatonin secretion in response to the day-night cycle.
A
  • The secretion of melatonin by the pineal gland (in darkness) is controlled by cells in the hypothalamus.
    Light exposure to the retina is relayed to the suprachiasmatic nucleus (SCN) of the hypothalamus. These fibers from the hypothalamus relay a message to the nerve ganglia of the spinal cord which is relayed back to the pineal gland to release melatonin.
31
Q

CIRCULATORY DISEASES

A
32
Q

B3.2.6: Causes and consequences of occlusions of the coronary arteries.
- State the function of the coronary arteries.

A

blood vessels that can be seen from the external surface of the heart; carry the most oxygenated, nutrient-rich blood from the aorta to the heart muscle tissue

33
Q
  • Outline the cause and consequence of a coronary occlusion.
A
  • Arthrosclerosis is the hardening and narrowing of the artery due to the deposition of cholesterol
  • Firstly, fatty deposits develop in the artery walls, decreasing the size of the lumen. This increases blood pressure, causing damage to the arterial wall due to sheer stress. The damaged region is repaired by fibrous tissue, but its elasticity is lost. As the smooth lining of the artery deteriorates, atherosclerotic plaques begin to form. If the plaque bursts, blood clotting is triggered, forming a thrombus that restricts blood flow. If the thrombus becomes dislodged, it becomes an embolus and can create blockages in arterioles.

Consequences of Coronary Occlusion
- Atherosclerosis can lead to blood clots which cause coronary heart disease when they occur in coronary arteries
- Myocardial tissue requires the oxygen and nutrients transported via the coronary arteries in order to function
- If a coronary artery becomes completely blocked, an acute myocardial infarction (heart attack) will result

34
Q
  • Evaluate correlations between diet and lifestyle variables and risk of coronary heart disease.
A

obesity (strain on heart), diet (type of fat), exercise, smoking (causes vasoconstriction)

35
Q
  • List factors that are correlated with an increased risk of coronary occlusion and heart attack.
A

A GODDESS

36
Q

gas exchange slide

A
37
Q

Define gas exchange.
State the role of diffusion in gas exchange.

A
  • Gas exchange is the exchange of gases between an organism and its surroundings, including the uptake of oxygen and the release of carbon dioxide in animals.
  • The exchange of gases between the individual cell and its environment takes place by diffusion. For example, in cells that are respiring aerobically there is a higher concentration of oxygen outside the cells than inside, and so there will be a continuous net inward diffusion of oxygen.
38
Q

Explain the need for structures of larger organisms to maintain a large enough surface area for gas exchange.

A

The surface area of a single-celled organism is large in relation to the amount of cytoplasm it contains, so the
surface of the cell is sufficient for efficient gaseous exchange. On the other hand, most cells in large multicellular organisms are too far from the surface of the body to receive enough oxygen by diffusion alone.

Animals often develop an external surface of tough or hardened skin that, while it provides protection to the
body, is not suitable for gaseous exchange. These organisms require an alternative respiratory surface.

  • Active organisms have an increased metabolic rate, and the demand for oxygen in their cells is higher than in
    sluggish and inactive organisms. Therefore, large, active organisms have specialized organs for gaseous exchange.
39
Q

B3.1.2: Properties of gas-exchange surfaces
Outline the function of the following properties of gas-exchange surfaces: permeability, thin tissue layer, moisture and large surface area.

A

Permeability – to allow the gases across

Thin tissue layer – to make the shortest distance for diffusion as possible

Moisture – gases dissolve in the moisture, helping them to pass across the gas-exchange surface

Large surface area – so that large quantities of the respiratory gases can cross at the same time.

40
Q

B3.1.3: Maintenance of concentration gradients at exchange surfaces in animals
State the reason why concentration gradients must be maintained at exchange surfaces.
Explain dense networks of blood vessels, continuous blood flow, and ventilation with air for lungs and with water for gills as mechanisms for maintaining concentration gradients at exchange surfaces in animals.

A
  • allows oxygen to diffuse into the body and carbon dioxide to diffuse out.
  • A dense networks of blood vessels: capillaries provide a large surface area for the diffusion of respiratory gases; blood carries the gases either in red blood cells (mainly oxygen) and plasma (carbon dioxide)

A continuous blood flow: this maintains the difference in concentration of molecules between the air and blood by carrying oxygen away from the gas-exchange surfaces in the capillaries and carbon dioxide to them

Ventilation: with air for lungs and with water for gills, ventilation brings oxygen to the gas exchange surface and removes carbon dioxide.

41
Q

B3.1.4: Adaptations of mammalian lungs for gas exchange
- State the locations of gas exchange in humans.
- Outline the structures of mammalian lungs that are adapted to maximizing gas exchange - including pneumocytes I and II

A
  • the alveoli and the capillaries
  • basically PMTL
  • Type I are very thin and allow rapid gas exchange (forms structure for alveolar walls)
  • Type II secrete a pulmonary surfactant that prevents the alveolar walls from sticking together/breaks surface tension
42
Q

B3.1.5: Ventilation of the lungs
- Identify the structure of the airway that connects the lungs to the outside of the body.
- Define ventilation

A
  • Trachea
  • Ventilation = exchange of air between the lungs and the atmosphere/ the flow of air in and out of the alveoli
    -Breathing in increases the concentration gradients of oxygen between the alveoli and blood - so it diffuses into the blood and binds to haemoglobin in the red blood cells.
    -Breathing out removes CO₂ (and unused O₂) increasing the concentration gradient of CO₂ between blood and alveolus - so CO₂ will diffuse out from the plasma into the alveolar air.
    -The gases can do this as high concentration gradients are maintained by ventilation changing the alveolar air and blood flowing through the capillaries covering the alveoli.
  • If the alveoli were not ventilated than equilibrium would be reached and no gas could be exchanged.
43
Q

why do we need a ventilation system?

A

maintains concentration gradient, allows blood to be a medium in which nutrient uptake and waste removal can occur, lungs are moist membranes allowing for diffusion to occur

44
Q
  • Define inspiration and expiration.
  • State the relationship between gas pressure and volume. (inversely proportional)
  • Outline the pressure and volume changes that occur during inspiration and expiration.
A
  • When the volume of the thoracic cavity increases, pressure in the thorax decreases
  • When the volume of the thoracic cavity decreases, pressure in the thorax increases
  • When the pressure in the chest is less than the atmospheric pressure, air will move into the lungs (inspiration)
  • When the pressure in the chest is greater than the atmospheric pressure, air will move out of the lungs (expiration)

Inspiration (inhaling) and expiration (exhaling) are controlled by two sets of antagonistic muscle groups

45
Q
  • Outline the direction of movement of the diaphragm and thorax during inspiration and expiration.
A

Antagonistic means working oppositely – when the inspiratory muscles contract, the expiratory muscles relax (and vice versa)

Inspiration
The muscles responsible for inspiration are the diaphragm and external intercostals (plus some accessory muscles)
Diaphragm muscles contract, causing the diaphragm to flatten and increase the volume of the thoracic cavity
External intercostals contract, pulling ribs upwards and outwards (expanding chest)
Additional muscle groups may help pull the ribs up and out (e.g. sternocleidomastoid and pectoralis minor)

Expiration
The muscles responsible for expiration are the abdominal muscles and internal intercostals (plus some accessory muscles)
Diaphragm muscles relax, causing the diaphragm to curve upwards and reduce the volume of the thoracic cavity
Internal intercostal muscles contract, pulling ribs inwards and downwards (reducing breadth of chest)
Abdominal muscles contract and push the diaphragm upwards during forced exhalation

heart test (3 decks)

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