Topic 2 Flashcards
List the 9 principal structures
of the ventilatory system.
*Nose
* Mouth
* Pharynx
* Larynx
* Trachea
* Bronchi
* Bronchioles
* Lungs
* Alveoli.
Outline the functions of the
conducting airways.
- Provide a low resistance air flow
- Defence against chemicals and other harmful substances that are inhaled
- No gas exchange occurs here,
- the air is warmed, moistened and filtered by the linings of the airways.
- Conducting airways are the nasal and oral passageways and the larger airways such as the trachea, bronchi and bronchioles.
- Debris and pathogens can severely damage the delicate exchange surfaces of the ventilatory system.
- A series of filtration mechanisms that make up the Respiratory defense system prevents such contamination.
Define the terms pulmonary
ventilation, total lung capacity
(TLC), vital capacity (VC),
tidal volume (TV), expiratory
reserve volume (ERV),
inspiratory reserve volume
(IRV) and residual volume (RV
Pulmonary ventilation: inflow and outflow of air between the atmosphere and the lungs (breathing).
Total lung capacity: volume of air in the lungs after a maximum inhalation.
Vital capacity: maximum volume of air that can be exhaled after a maximum inhalation.
Tidal volume: volume of air breathed in and out in any one breath.
Expiratory reserve volume: volume of air in excess of tidal volume that can be exhaled forcibly.
Inspiratory reserve volume: additional inspired air over and above tidal volume.
Residual volume: volume of air still contained in the lungs after a maximal exhalation
Explain the mechanics of
ventilation in the human
lungs.
1 During exercise when more oxygen is needed by the active muscles and more carbon dioxide is being produced by the muscles, more air needs to be inhaled and exhaled at a faster rate.
2 Increase rate and bolume (biggerdeaper breaths) and faster
3 use of shoulder pectoral grade increases volume
4 greater need to intake air
5 To achieve this additional muscles in the chest wall (external intercostals, abdominals, even shoulders) are used to increase the lung volume during inhalation.
6 - Inhalation - passive
- Diaphragm contracts and lowers
- External intercostal muscles contract
- This causes the rib cage to move upwards and outwards
- The volume of the chest cavity increases
- The pressure inside the lungs drops below atmospheric pressure
- Boyle’s Law
- Air rushes into the lungs
- Exhalation - active
- The diaphragm relaxes and turns to a dome shape
- Internal intercostal muscles contract
- This causes the rib cage to move downwards and inwards
- The volume of the chest cavity decreases
- The pressure inside the lungs increases above atmospheric pressure
- Air is forced out of the lungs and into the atmosphere
accessory muscles are also important during
strenuous exercise
Describe nervous and
chemical control of
ventilation during exercise.
Limit to ventilation increases as a direct result of
increases in blood acidity levels (low pH) due to
increased carbon dioxide content of the blood
detected by the respiratory centre. This results in
an increase in the rate and depth of ventilation.
Neural control of ventilation includes lung
stretch receptors, muscle proprioreceptors and
chemoreceptors.
The role of H+
ions and reference to partial
pressure of oxygen are not required
- Homeostasis
The maintenance of a constant internal environment
- Many systems in the body are continuously working in a highly coordinated manner to keep a large number of variables at, or as close as possible to, resting levels.
- Exercise presents a number of challenges to the homeostasis of the body.
- Homestatic Control
Systems work together to regulate variables such as
- oxygen content of arterial blood
- acid base status
- core body temperature
Ventilation increases as a direct result of increases in blood acidity levels due to increases in carbon dioxide content in the blood, which is detected by the respiratory center
this results in an increase in the rate and depth of ventilation-
Hmoglobin picks up o2 around alveoli, hemoglobi picks up o2 increasing air pressure in arterial blood , o2 dissacociates into body cells
Outline the role of
hemoglobin in oxygen
transportation.
Most (98.5%) of oxygen in the blood is transported by hemoglobin as oxyhemoglobin within red
blood cells
Explain the process of
gaseous exchange at the
alveoli.
Alveoli: tiny air sac at the end of bronchioles
→ very thin walls (one epethelial cell thick to allow movement)
→ form large surface area for optimal gas exchange
→ dense network of capillaries: rapid supply
→ moist lining, aiding gases in dissolving
Gases move between alveoli and the bloodstream by diffusion down the concentration gradient that is created by the alveoli (high to low).
An exchange of oxygen and CO2 happens at the alveoli:
- Alveoli fill up with oxygen from inhalation → higher concentration tahn bloodstream so diffuse across membrane into bloodstream
- at the same time as oxygen moves out of the alveoli the concentration becomes lower so concentration pf CO2 in blood is higher → diffuses across membrane into alveoli to be exhaled
State the composition of
blood.
Blood is composed of cells (erythrocytes, leucocytes and platelets) and plasma. Blood is also the transport vehicle for electrolytes, proteins,
gases, nutrients, waste products and hormones
55% plasma
less than 1% Platelets
less than 1% Leucocytes (White Blood Cells)
40-45% Erythrocytes (Red Blood Cells)
Distinguish between the
functions of erythrocytes,
leucocytes and platelets.
- 55% plasma -90% water, straw coloired, 8% blood proteins, 1% salts, food substances and waste and gas enzymes antibodies antitoxiens straw colouredfluid carries the RbC WBC plateltts dissolved gases/nutrients
- < 1 % Plateletsassist the repair process following injuryThere are between 150,000 and 400,000 platelets per microlitre of blood.Platelets contain chemical which promotes vascular spasm and clotting by forming a platelet plug.Platelets have a shortlifespan of just 5-9 days.
- < 1 % Leucocytes (White Blood Cells)) - primarily involved in the immune systemThey defend the body against invasion by pathogens and they remove toxins, waste and abnormal of damaged cells.5000- 10 000 WBC per microlitreMost of the bodies WBC are in connective tissue or in the organs of the lymphatic system.Circulating WBC represent only a small fraction of the total WBC population.
- 40-45% Erythrocytes (Red Blood Cells)
- FunctionThe primary function of blood is to transport to and from various tissue. Nutrients, gases wasterproducts, hormones , electrolytes, proteins and heatdsContain an oxygen-carrying pigment called hemoglobin (protein), which gives blood
its red color
- FunctionThe primary function of blood is to transport to and from various tissue. Nutrients, gases wasterproducts, hormones , electrolytes, proteins and heatdsContain an oxygen-carrying pigment called hemoglobin (protein), which gives blood
Describe the anatomy of the
heart with reference to the
heart chambers, valves and
major blood vessels.
get empty diagram
The names of the four chambers, four valves (bicuspid, tricuspid, aortic and pulmonary valves) and the four major blood vessels (vena cava, pulmonary vein, the aorta and pulmonary artery) of the pulmonary and systemic circulation are required. The heart has its own blood supply via the coronary arteries; however, the names of the coronary arteries are not required
- ArteriesElastic arteries: the largest in the bodyeg garden hosed sized aorta and pulmonary artery (trunk) to finger sized branches of the aorta,large diameter but relatively thin wall (1/10 of total diameter), smooth muscle and elastic fibres in vessel walls
- they propel blood onward while the ventricles are relaxing
- as the blood is ejected from the heart the wall stretch to accommodate the surge of blood.
- the elastic walls store the mechanical energy, then the elastic fibres recoil pushing the blood onward to the…
- Capable of greater vasodilation and and vasoconstriction. to adjust blood flow.
- Do not have the ability to recoil.
- Vascular tone: the ability for the smooth muscle to contract and maintain contraction. important in maintaining efficient blood flow and vessel pressure.
- CappilariesCapillaries: smallest blood vessels , very thin walls, walls composed of single layer endothelial cells a base membrane, diameter of 5-10 µm. ‘exchange vessels’
- RBC’s have a diameter of 8µm must therefore fold up on themselves to get through single file.
- 20 billion in number, branching and interconnecting.
- creating an enormous surface area to contact with the bodies cells
- Primary function is the exchange of substances between the blood and interstitial fluid.
- the higher the metabolic rate the more extensive the capillary network eg brain, liver, muscles, lungs.
- at low metabolic levels only part of the network has blood flowing through (precapillary sphincters)
- consider muscle at rest and during exercise.
- VeinVein: very thin walls relative to diameter, not designed to withstand high pressure. 0.5mm to the Vena Cava (approx 3 cm)
- Smooth muscle no elastic fibres.
- Contain valves - prevent back flow
- Pumping action is a major factor in moving venous blood back to the heart.
- Contraction of skeletal muscle in the lower limbs boost venous return.
- Blood pressure in veins considerably lower than arteries
- Consider a severed artery vs a severed vein.
Muscular Venules: Microscopic 50-200µm, one or two layers of smooth muscle.
Describe the intrinsic and
extrinsic regulation of heart
rate and the sequence
of excitation of the heart
muscle
The heart has its own pacemaker, but heart rate is also influenced by the sympathetic and parasympathetic branches of the autonomic nervous system and by adrenaline. (It should be
recognized that adrenaline has wider metabolic actions, that is, increasing glycogen and lipid breakdown.) The electrical impulse is generated at the sinoatrial node (SA node) and travels across the atria to the atrioventricular node (AV node) to the ventricles
- Intrinsic and extrinsic regulation of heart rate
Cardiac muscle generates its own contractions these are called MYOGENIC CONTRACTIONS
These myogenic contractions are generated by the Autonomic Nervous System (ANS)
The ANS has 2 subdivisions which work in opposition.
Parasympathetic Nervous System (PNS) - restores bodily systems to rest. eg the decreasing Heart rate after exercise
Baroreceptors ( aorta and carotid arteries) respond to high blood pressure received by cardiac inhibitory centre transmitted via VAGUS nerve (PNS) to slow heart rate
Sympathetic Nervous System (SNS) - Prepares body for action eg Increasing heart rate.
- Adrenaline
## **Cardiac Accelerator centre**
## **releases Noradrenaline onto SA node (SNS)**
## **Adrenaline: released from adrenal medulla**
- prepares body for action
- targets heart
- blood vessels
- liver and fat cells
## **Stimulates:**
- glycogenolysis
- intracellular metabolism of glucose in muscle cells
- break down of fats and protein to form glucose
Responds to a range of stimuli to maintain homeostasis
- Sequence of excitation of the heart muscle
- IntrinsicPacemaker system
- Starts in the right atrium
- A cardiac impulse is initiated from the sino-atrial
(SA) node (pacemaker) - The impulse causes the atria to contract
- Cardiac impulse reaches and activates the
atrioventricular (AV) node - This passes the impulse down Bundle of His (in
the septum of the heart) - Bundle of his splits left and right, up around the
heart (Purkinje fibers) - The impulse is spread around the walls of ventricles causing them to contract
- Ventricles relax and the cycle starts again
the autonomic nervous system
and by adrenaline. (It should be
recognized that adrenaline has
wider metabolic actions, ie
increasing glycogen and lipid
breakdown.) The electrical
impulse is generated at the
sinoatrial node (SA node) and
travels across the atria to
the atrioventricular node (AV node) to the ventricles.
- IntrinsicPacemaker system
Outline the relationship
between the pulmonary and
systemic circulation.
- Pulmonarycarries deoxygenated blood away from the heart to the lungs and returns oxygenated blood back to the heart
- Systemic Circulationcarries oxygenated blood away from the heart to the body and returns deoxygenated blood back to the heart
Describe the relationship
between heart rate, cardiac
output and stroke volume at
rest and during exercise
Cardiac output = stroke volume × heart rate.
Stroke volume expands and heart rate increases
during exercise
Analyse cardiac output,
stroke volume and heart
rate data for different
populations at rest and
during exercise.
Heart Rate (HR): Beats per minute.
Stroke Volume (SV): Blood pumped per beat.
Cardiac Output (CO): Total blood pumped per minute (HR × SV).
At Rest:
Males/Females: Males typically have higher SV, lower HR, and slightly higher CO than females.
Trained/Untrained: Trained people have higher SV and lower HR, so similar or higher CO than untrained.
Young/Old: Young people generally have higher SV and lower HR than older adults, with CO similar or slightly higher.
During Exercise:
Males/Females: Both increase HR and SV; males still tend to have higher SV and CO.
Trained/Untrained: Trained individuals have higher SV, slower HR rise, but greater CO compared to untrained.
Young/Old: Younger individuals have a greater capacity to increase HR and SV, resulting in higher CO than older adults.
V>E Minture Ventialtion = B>f x Todal Volume ml/L
- cardiac outputcardiac output = stroke volume x heart rate
Q = SV x HR
Explain cardiovascular drift.
Cardiovascular drift is an icnrease in heart rate during prolonged exercise (despite same effort)
prolonged exercise increases temperature, blood redistributed to skin to cool water is lost via sweating.
blood volume redistribution causes heart to work harder to maintain muscle blood flow/energy demands
prolonged cooling causes decrease in blood volume/increase in viscosity
redduction in venous return/stroke volume causes the HR to increase to maintain cardiac output.
- Outlinecardiovascular drift is the gradual increase in HR seen in an athlete doing prolonged ‹steady state› exercise✔dehydration contributes to cardiovascular drift✔cardiovascular drift is associated with increased blood viscosity✔over prolonged periods of exercise stroke volume decreases✔blood being sent to the skin/vasodilation for cooling reduces stroke volume to active muscles causing HR to increase✔to maintain cardiac output HR increases✔exercise in a hot environment exaggerates cardiovascular drift✔
