THE CARIDOVASCULAR SYSTEM Flashcards

Question

CARDIAC OUTPUT

Answer 1

- the amount of blood ejected from each ventricle every minute - The amount expelled by each contraction is the stroke volume Stroke volume X heart rate = cardiac output Stroke volume is dependent on: > preload ( volume of blood in ventricles at the end of ventricluar filling affecting ciruclation = reducing it = loss of blood, loss of fluid from drugs: diuretics and when mechanism maintian blood pressure affected by drugs = dillate the blood vessels: blood volume in the heart at the end of diastole (affected by circulating volume aterial pressure and peripheral resistance - increasing pressure against which ventricles have to work (systemic blood pressure) > afterload - the resistance that the ventricles have to work against, being very cold or stressed, can affect this, as well as high blood pressure .> contractility - myocardium strength of contraction, losing the ability to stretch and contract. How strongly the heart is able to contract and can be affected by heart faliure FACTORS THAT CAN AFFECT HIGH BLOOD PRESSURE: - autoonmic activity - hormones - gender - age - temp - emotional states FACTORS AFFECTING STROKE VOLUME - heart size - fitness level - biological sex - afterload cardiac output (co) = HR X SV

Answer 2

- rate dependent becasue the myocardium = less contractile: neonates and infants = prone to bradycardias due to dominate parasympathetic tones - cardiac output is different in adults because of the difference in contractility of the heart in different ages

Answer 3

- increase in cardiac output - increase in blood volume - increase in stroke volume - decrease in peripheral vascular resistance - decrease in diastolic blood pressure - increase in heart rate - increase in venous pressure -hypertension - In the first half of pregnancy CO increased by stroke volume - 3rd trimester increases heart rate - pregnacy changes the cardiovascular reposne to excersie - compression of inferior vena cava during thrid trimester = venous return = limited & prevent SV from increasing which usually happens during excersie

Answer 4

- forced the blood to exert the wall of blood vessels - left ventricle contracts, pushes blood into the aorta = blood pressure rises = systolic blood pressure - cardiac diastole - resting for refill = diastolic blood pressure as arterial pressure drops PERIPHERAL RESISTANCE: - Resistance is dependent on lumen diameter + regulated in the smooth muscle of the tunica media. length of tube + viscosity of fluid - maintiang blood fow + dependent on the CO - peripheral resistance (diamiter of the resistance vessels) heart needs pressure to pump against - tissue perfusion is dependent on blood pressure = maintian the flow of blood to body tissue = allowing nutrient + O2 requriment are met - autorgulation (the ability of an organ to control its own blood flow through vasoconstriction and vasodilation - Autonomic nerve fibres supply smooth muscle in the tunica media and control the diameter (elasticity to push and recoil to exert the blood forward maintaining the pressure) of the main arteries - smaller arteries/arterioles have more smooth muscle thus less elasticity, important in controlling peripheral resistance. - veins contract/constrict a little = difference to bp - pulse pressure - difference between systolic and diastolic blood pressure - high blood pressure = damages blood vessels

Answer 5

MICROSCOPIC AIRWAYS RESPITORY BRONCHIOLES - ALVEOLAR DUCTS - ALVEOLAR SACS - ALVEOLI (where gas exchange happens)

Answer 6

PULSE - pressure waves travelling through the arteries - represents the heart rate - Regularity of the heartbeat - volume & strength of the beat (compression should stop the flow, giving an indication of BP and the vessel wall - TENSION: artery wall should feel soft and pliant under fingers BRADYCARDIA: <60bpm TACHYCARDIA: > 100 bpm - heart beat = pulse beat - pressure wave created by the heartbeat = not strong enough - apex/radial deficit, heart beat is faster than pulse

Answer 7

- compliance of the heart failure - decline of cardiovascular function - cardiac output falls - Conduction pathways are less efficient - cardiac muscle cells numbers decline - hypertrophy (enlargement) - Regulation of blood flow is less efficient (vasodilation) - hardening/stiffening of arterial walls = increase in BP - Baroreceptors reflex less brisk = neurological ageing

Answer 8

- walls made up by a single layer of squamous epithelial cells = type 1 alveolar cells surrounded by a flimsy membrane Type 2: (septal cells) are cuboidal epithelial cells scattered among type 1 cells. These secrete surfactant (a detergent-like substance) that coats the alveolar surface, stops alveoli drying out, reduces surface tension, and is gas-exposed, preventing alveolar collapse during expiration. - Secretions of surfactant in the 35th week of fetal life - external surface of alveoli covered with "cobweb" pulmonary capillaries, blood flowing past on one side & gas exchange on other

Answer 9

- Pulmonary trunks divide into right and left pulmonary arteries, carrying deoxygenated blood into the lungs - Within the lungs the pulmonary arteries divide into branches in a dense capillary network around alveoli - exchange of gases between air in the alveoli and blood in capillaries happnes when pulmonary capilliares merge into networks from the two pulmonary veins carrying oxygenated blood back to the heart

Answer 10

- process of moving into (inspiration and out (expiration) of lungs - Average respiration for an adult is 12-15 breath per minute, varying in children = breath in higher rates due to smaller lung volume + metabolise at higher rates (need to get rid of more CO2 - breathing/pulmonary ventiliation = process of moving air into & out of lungs = supplying O2 to alveoli & get rid of CO2 There are muscles involved in breathing. These include 11 pairs of intercostal muscles occupying the space between the 12 pairs of ribs. Our internal intercostal muscles are involved in active expiration, like when we exercise, and the external intercostal muscles are involved in inspiration. - DIAPHRAGM: dome-shaped, separates the thoracic cavity from the abdominal cavity, attached to muscle fibres to lower ribs and sternum - inspiration external intercostal muscles and diaphragm contract = enlarging throatic cavity - muscles include: sternocleidomastoid muscles and the scalene muscles = limkl vertebrae to first 2 ribs & increasing ribcage expansion.

Answer 11

PHASES: > inspiration > Expiration > pause (rest) _ relying on change in pressure & volume in thoratic cavity - The volume container the increase, the pressure of gas inside decreases and the volume of container decreases the pressure of gas increase

Answer 12

- pressure inside the lung = reduced & lower than atmospheric pressure air with naturally flowing into the lungs until no pressure difference - INSPIRATION = needs energy for muscle contraction - Breathe out. The volume of our chest cavity reduces, so the pressure increases above atmospheric pressure. Therefore, air moves out of our lungs and into the atmosphere. - Expiration is a passive process as it doesn’t require any energy. After expiration, there is a pause before the next cycle begins. - As air will naturally flow from an area of high pressure to an area of low pressure.

Answer 13

- O2 diffusing alveoli into blood & CO2 diffusing from blood into lungs - dependent on partial pressure differences - diffuse from an area where partical pressure is higher to an areas where partical pressure is lower - External respiration/ gaseous exchange is how oxygen diffuses from the lungs (alveoli) into the bloodstream and how CO2 diffuses from the blood to the lungs. - Gas exchange is a process that is happening continuously in our bodys. The diffusion of oxygen and carbon dioxide is dependent on pressure differences - Atmospheric air is a mixture of gases - nitrogen, oxygen, carbon dioxide, water vapour and small amounts of inert gases. - Each gas in this mixture exerts a part of the total pressure proportional to its concentration i.e. the partial pressure (PO2 and PCO2). (Dalton's Law is another useful gas law to be aware of that states - the total pressure of a mixture of gases, is equal to the sum of the partial pressures of the individual gases). - respiratory system as the differences in partial pressure dictate the movement of oxygen and carbon dioxide between the atmosphere, the lungs and the blood.

Answer 14

- thin membrane - The cell wall is one cell thick = short diffusion distance - large surface area of the alveolar membrane - large surface area of capillaries

Answer 15

- blood arriving into lungs from pulmonary artery travelled from body tissue = high level of CO2 and low level of O2 - CO2 moves down the concentration gradient from blood to alveoli until alveolar air = reached - same process O2 diffusion from alevoli into blood ready travelling back to heart via pulmonary vein to pumped around body tissue

Answer 16

- exchange of gases by diffusion between the blood in the capillaries and the cell body - diffusion of gases across capillary membranes in tissue - Internal respiration is an exchange of gases by diffusion between blood in capillaries and the body cells - gas exchange doesn't happen across the walls of arteries carrying blood from the heart to the body tissue = too thick - blood arriving @ capilairies contain PO2 as blood leaving the lungs - blood saturated with O2 in lungs has a much higer PO2 and lower PCO2 than tissue - concentration gradient between capillary blood and tissue = O2 diffuses through the capilairy wall into blood tissue from blood and CO2 diffuses into the bloodstream

Answer 17

- carried in bloodstream by protein (haemoglobin) found in erythrocytes (oxyhaemoglobin) - Erythrocytes contain millions of haemoglobin proteins, each haemoglobin can carry 4 oxygen molecules. - Amount of oxygen that is attached to haemoglobin at a given time is measured as an oxygen saturation (SaO2).

Answer 18

Carbon dioxide is one of the waste products of metabolism. It is excreted by the lungs and is transported by 3 mechanisms. - Bicarbonate ions (HCO3-) in the blood plasma (70%) - Combined with haemoglobin in the erythrocytes as - carbaminohaemoglobin (23%) Dissolved in the blood plasma (7%) - CO2 levels must be managed carefully as an excess or deficiency leads to significant disruption to our acid-base balance which is the levels of acids and bases (Base (alkaline) - a substance that can neutralize acid by accepting hydrogen ions) in your blood which your body functions best at, the pH balance of the body.

Answer 19

- When breathing the lungs and air passages are never completely empty and there are different volumes to be aware of. - Tidal volume (TV) - this is the amount of air passing in and out of the lungs in one breath. - Inspiratory reserve volume (IRV) - amount of air that can be forcibly inspired beyond the tidal volume - Expiratory reserve volume (ERV) - amount of air that can be expelled from the lungs after a normal tidal volume expiration - Residual volume (RV) - amount of air left in lungs even after largest expiration - cannot be directly measured. - Inspiratory capacity - total amount of air that can be inspired after a normal tidal volume so it is the sum of TV and IRV. Functional Residual capacity - amount of air remaining in lungs after a normal tidal volume expiration so is the sum of RV and - - ERV - prevents alveoli collapse on expiration. - Vital capacity - maximum volume of air that can be moved in and out of the lungs so is sum of TV+IRV+ERV - Total lung capacity - the maximum amount of air the lungs can hold - in average adult is around 6 litres. The sum of TV+IRV+ERV+RV cannot be directly measured in tests because even after forced expiration, the RV of air still remains in the lungs. - Lung function tests can be carried out to determine respiratory function, which can help in diagnosing and monitoring respiratory disorders.

Answer 20

Measurement of lung ability to stretch and expand by: > elasticity of the lung tissue > alveolar surface tension - Lung tissue is very elastic and surfactant, produced by cells found in alveoli, keeps surface tension in the alveoli low therefore healthy lungs tend to be incredibly compliant.

Answer 21

RESPITORY CENTRE: a group of nerves in the medulla and pons 3 important groups: > inspiratoru group (rhythm of breathing (basic)) > Expiratory group (controls expiration) > neruons in pneumotaxic area (regulate rate & depth of breathing) - Effective control of breathing enables the body to regulate blood gas levels physiological, environmental and (pathological conditions and is normally involuntary.) - We can voluntarily control our breathing during activities such as speaking and singing but if CO2 levels rise this is overridden. - In the brain is an area that is known as the respiratory centre, which is located in the brain stem in the medulla. - Groups of nerves which control the respiratory rate and depth of breathing. The 3 important groups of neurones here include the inspiratoryts the basic rhythm of breathing), the expiratory group (which controls expiration), and neurones in the pneumotaxic area (which are located in the pons and help regulate th group (which see rate and depth of breathing).

Answer 22

- Motor impulses leave the respiratory centre and pass in the phrenic nerve and intercostal nerves to the diaphragm and intercostal muscles to stimulate respiration. - Alongside the respiratory centre controlling breathing, breathing is also influenced by information coming in from the periphery - most importantly chemoreceptors which are located centrally in the brain and in the arch of the aorta of the heart. - These receptors respond to changes in the partial pressures of oxygen and carbon dioxide in the blood. For example if there is a rise in CO2 levels detected by these chemoreceptors, nerve impulses are triggered to the respiratory centre, stimulating the respiratory centre which increases the rate and depth of breathing in order to reduce CO2 levels in the blood.

Answer 23

1. Decreased Lung Elasticity What happens: The elastic tissues in the lungs become less stretchy with age. Effect: This makes it harder for the lungs to expand and contract fully, reducing lung capacity and efficiency in gas exchange. 2. Weaker Respiratory Muscles What happens: The diaphragm and intercostal muscles weaken over time. Effect: Breathing becomes less efficient, especially during exertion or illness. 3. Reduced Alveolar Surface Area What happens: The number and surface area of alveoli (air sacs) can decrease. Effect: Less area is available for oxygen and carbon dioxide exchange. 4. Stiffer Chest Wall What happens: The ribs and cartilage become more rigid due to calcification. Effect: It’s harder to expand the chest during breathing, leading to shallower breaths. 5. Diminished Cough Reflex and Ciliary Function What happens: Cilia (tiny hairs that clear mucus) slow down, and the cough reflex weakens. Effect: Mucus and pathogens are cleared less efficiently, increasing the risk of infections like pneumonia. 6. Decreased Respiratory Reserve What happens: Maximum breathing capacity and oxygen uptake decline. Effect: Older adults may tire more quickly and are less able to tolerate respiratory stress.

THE CARIDOVASCULAR SYSTEM Flashcards

(48 cards)