Topic 2 Flashcards
Principal structures of the ventilatory system
Nose, mouth, pharynx, larynx, Trachea, Lungs, Bronchi, Bronchioles, Alveoli, Diaphragm
Functions of conducting airway
- Low resistance pathway of airflow
- Warming and moisturizing air
- Defense against chemical and other harmful substances in inhalation
Define Pulmonary Ventilation
Movement of air in and out of lungs
Total lung capacity
The volume of air in the lungs after max inhalation
Vital capacity
The amount of air that can be exhaled after max inhalation
Expiratory reserve volume
The amount of air an individual can exhale beyond tidal capacity
Inspiratory reserve volume
The amount of air an individual can inhale above a tidal inspiration
Residual volume
Volume of air still contained in lungs after max exhalation
Mechanism of ventilation
Inhale:
- Diaphragm contracts and lowers, external intercostal muscles contract
- Rib cage moves up and outwards
- The volume of the chest cavity increases
- Pressure inside the lungs drops below atmospheric pressure
- air rushes into lungs
Exhale:
- Diaphragm and intercoastal muscles relax and return to resting postition
- Causes rib cage to move down and inwards
- The volume fo the chest cavity decreases
- The pressure inside the lungs increase above atmospheric pressure
- Air forced out
Nervous and chemical control of ventilation during exercise
The drive to breathe comes from an increase in CO2 in blood : causes pH levels in blood to decrease and increase in acidity
- Change in pH levels is detected by chemoreceptors located in aorta and common carotid arteries. It sends signal to respiratory center in the brain stem. Which stimulates pherenic nerve, controls diaphragm and other nevers in external intercostal muscles. Increasing the rate and depth of breathing
- Stretch receptors in the walls of bronchi and bronchioles activate when lungs expand to their physical limit. Signals to the respiratory center to stop stimulation of the inspiratory muscles= allowing expiration to start
This is called hering Breuer reflex which prevents damage in the lungs - Blood pressure receptors (baroreceptors) in aorta and carotid arteries. Respond to decreased blood pressure causing increase in breathing rate. or increased blood pressure cuasing decrease in breathing rate.
- Stretch receptors in muscle indicate movement= increase breathing rate to prepare for physical activity
- Voluntary control: respiration can be affected by higher brain conditions: emotional state via input from the limbic system, temprature via the hypothalamus, free will (choosing to hold breath). provided via the cerebral cortext, although chemoreceptors reflex is capable of overriding it
Hyperventilation before diving into water
The drive to breath comes from the presents of carbon dioxide and not the absense of oxygen.
Hyperventilation before diving underwater:
the individual blows off extra carbon dioxide. so when underwater the carbon dioxide in lungs is lower than normal. it accumulates at normal rate however, will take longer to reach the critical point. Therefore, the individual will experience a lack of oxygen which can cause them to drown as they may fall unconsious
Hemoglobin in oxygen transporation
· 98. 5% of oxygen In the blood is transported by hemoglobin as oxyhemoglobin within red blood cells
· hemoglobin is a protein allows oxygen to bind to a red blood cell
· it contains a central Iron on which can hold up to 4 oxygen atoms per heme
· oxygen atoms are then diffused into tissues once they reach their target
· While diffusing they are picking back up CO2 (carbon dioxide), returning it back to longs so you can exhale
Gaseous exchange at alveoli
-Delivery of Oxygen from lungs to bloodstream, and carbondioxide to lungs from bloodstream
-> occurs in longs between the alveoli and capillaries
2. Oxygen from Inhalation diffuses through the walls of the alveoli and into the capillaries to the red blood cells
2. The red blood cells cary the oxygen to the body (oxygenated)
3. CO2 which is produced by the body return to the lungs in the red blood cells (deoxygenated)
4. The CO2 diffuses across the capillary and the alveolar walls into the mir so that it can be removed from exhalation
Adaptions of the alveoli
-> Walls of the alveoli are one cell thick
-> They are folded, providing a larger surface area
-> They are surrounded by capillary which allow the good blood supply
Composition of blood
Blood -a specialized type of connective tissue
· Erythrocytes-red blood cells -> 99% of the formed element in the blood
· Leukocytes-White blood cells
· Platelets-create a meshwork of fiber to help with clotting
· Plasma-colorless fluid that contains water, protein and nutrients
Functions of blood compositions
Erythocytes (red blood cells)
· contain an oxygen-carrying pigment called hemoglobin (protein), which gives blood its red color
· Transports notrients, oxygen, carbon dioxide, waste products and hormones to cells and organs around the body
Leukocytes (white)
· help fight against infection and inflammation
Platelets
· cells with no nucleus
· involved in process of clotting to repair blood vessels: meshwork
Anatomy of the heart
Right side (deoxygenated blood)
- Superior vena cava recieves blood from head, neack, upper limbs, chest.
- Inferior vena cava recieves blood from trunk and lower limbs.
- Enters right atrium
- Tricuspid value
- Right Ventricle
- Pulmonary semilunar valve
- Pulmonary artery: left right lung (gaseous exchange occurs)
- Blood comes back from lungs into pulmonary vein
- Left Atrium
- Bicuspid valve
- Left ventricle
- Aortic semilunar valve
- aorta
1. Branchiocephalic artery 2. Left common carotid artery 3. subclavian artery 4. Descending aorta
Intrinsic regulation of heart rate
increased HR we also 402 delivery to muscle we can& rate of herobic energy production = glycogen and lipids (fats)
Intrinsic regulation -it is self-regulating and maintains its own rythm without direction
1. Sinoatrial node (SA)-pacemaker sends a stimulus across the walls of the
right and left atrium-Causing them to contract
2. The stimulus arrives at the Atrioventricular node (AU)
3. The stimulus is directed to follow the AV bundle (bundle of his)
4. The stimulus travels through the apex of the heart through the bundle branches
5. The Purkinje fibers distribute the stimulus across both ventricles
↳ causing a ventricular contraction
Extrinsic
Medualla oblongata - cardiac control center
Controlled by the autonomic nervous sytem
Symphatetic nerves (fight or flight).
- increases heart rate.
- Adrenaline is secreted = impact on glycagon and lipid breakdown for enegry
- Bronchi are dilate to allow more air into the lungs
- digestive system is restricted with blood flow = going to heart and muscle
Parasympathetic nerves (rest and digest) -
- decreases HR.
- Acetylcholine is released.
- Bronchi is constricted allowing not as much air into lungs
- Digestive system promote blood flow.
Systematic circulation and pulmonary circulation
Systemic circulation -carries oxygenated blood away from the heart to the body and returns deoxygenated blood back to the heart
pulmonary circulation -carries deoxygenated blood away from the heart to the longs and return oxygenated blood back to the heart
Heart Rate, Cardiac Output, Stroke Volume
heart rate (HR)-The number of times the heart beats per min (bpm)
stroke volume (SV)-The amount of blood pumped by each ventricle per beat (liters)
Cardiac output (Q)-The amount of blood pumped from the heart In one minute (liters)
Cardiac output = Stroke volume x heart rate Q = HRX SV
When the body starts to exercise there is a higher demand of oxygen, causing HR, SV, Q to increase
venous return: the amount of blood returned to the right side of the heart
↳ less blood returned meaning UR is increasing
Cardiovascular drift
Thermoregulation response to prolonged exercise.
Body enters stage of dehydration = excessive heat
Submaximal exercise and over 30 min
- Heat is produced as a byproduct of energy production
- The excess heat increases the core body temp to 37-40 degrees
- This causes the blood to redistribute the heat from the internal area to the skin.
- Vasodilation of the blood vessels under the skin is responsible for movement of the heat
- Evaporation occurs at the skin allowing heat to dissipate and so as fluid/sweat evaporates
- Causes reduction of blood plasma, increasing blood viscosity, in turn decreasing SV and Venous return.
- This reduction in SV places and increase in demand on heart rate to maintain a steady cardiac output.
Anaylse Q, SV, HR data for different populations at rest and during exercise
Systolic and diastolic blood pressure
systolic blood pressure -the force exerted by blood on the arterial walls during contraction
Diastolic blood pressure -the force exerted by blood on arterial walls during relaxation
Systolic and diastolic blood pressure at rest and during exercise
During rest: Systolic pressure is lower, Diastolic pressure is lower
During exercise: Systolic pressure is higher, Diastolic pressure does not raise as much as systolic
Diastolic and Systolic blood pressure in response to dynamic and static exercise
static: Holding exercise In a single position ex: Weightlifting, wall sit
Dynamic: moving muscle and joint with large motion eg: running, swimming
Dynamic: S= up, staight D= Staight
Static: S: up more D= up less
Distribution of blood at rest and the redistribution of blood during exercise
During exercise, more blood goes to the muscle
Rest: 1. Liver 2. Kidneys, muscles 3. Brain
Exercise: 1. Muscles!!!
Cardiovascular adaptations resulting from endurance exercise training
· resting heart rate decreases
· Stroke volume/left ventricular volume Increases
↳ because of heart hypertrophy
· Increased capillarization
↳ The muscles are sorrounded by an Increase in capillaries that allow more oxygen supply
· Arterio-venous oxygen difference increases
↳ this is due to adaptations in the Mitochondria, Increased myoglobin and improved capillarization
Maximal oxygen consumption
VO2 max-> max amount of oxygen that can be consumed during maximal intensity
↳ Those with higher fitness level will have higher VO2 max = can exercise more intensely than those who are not as well conditioned
· It reflects the ability of the body to dilever oxygen to muscle and use it to produce energy during exercise
Absolute = litres per min (7/min)
relative-millileters per kilogram per minute (m/kg/min)
Variability of Vo2 Max in selected groups
Trained individuals: higher Vo2 Max
Males: higher
Age: decile with age
Endurance athlete: Higher
Variability of Vo2 max with different exercises
Running: high level of Intensity, large muscle groups = higher demand
for oxygen and a greater increase in VO2 max
Cycling: Smaller muscle groups, higher intensity for longer = VO2 max values
Arm ergometry: Smaller and les powerful muscles used = In smaller VO2 max
