The Cardiac and Respiratory Systems Flashcards
What is the purpose of the epiglottis?
protects the larynx from food by closing over it during swallowing
What does the larynx contain which relates to an effective cough?
contains vocal chords (glottic)
Is the trachea situated posteriorly or anteriorly to the oesophagus?
anteriorly
Why is there cartilage in the trachea?
to prevent tracheal collapse during pressure changes
- C-shaped rings supporting the anterior and lateral aspects, not posteriorly to allow oesophagus to expand anteriorly as food is swallowed
Parietal pleura
lines the inner surface of the thoracic wall and superior surface of the diagram
Visceral pleura
covers the outer surface of the lungs and lines the fissures
Pleural membrane
double-layered serous sacs that cover the lungs
Pleural cavity
space between the 2 layers (contains pleural fluid)
Pleural fluid
- acts as a lubricant allowing layers to glide over each other during inspiration and expiration
- increases surface tension ‘locks’ 2 pleural layers together
What 2 muscles are used for inspiration?
- diaphragm
- external intercostals
What are 2 accessory muscles of inspiration?
- sternocleidomastoid
- scalenes (x3)
What 3 muscles are used for forced expiration?
- internal intercostals
- rectus abdominis
- internal and external obliques
Atelectasis
collapse of alveoli and segment of lung tissue
Describe how relaxed inspiration takes place.
- controlled by impulses from the respiratory centre in the brainstem
- nerve stimulation causes contraction of the diaphragm and outer intercostals (expands thoracic cage and lungs)
- expansion creates lower pressure (relative to outside the body)
- air rushes in
Describe how the abdominal muscles cause forced expiration.
abdominal muscles contract, causing the abdominal contents to push up against the diaphragm - reducing the vertical diameter of the thorax
Where does the ciliated epithelium line?
- nasopharynx
- pharynx
- trachea
- bronchi
- bronchioles
What are the (3) sub-divisions of the pharynx?
- Nasopharynx
- Oropharynx
- Laryngopharynx
What does the larynx contain?
vocal cords
What is the glottic (vocal cord) function essential for?
an effective cough
Where does the trachea birfucate?
the carina (into the R&L main (primary) bronchi)
What angle does the right main bronchus branch off at?
20-30°
What angle does the left main bronchus branch off at?
45-55°
Describe the secondary/lobar bronchi.
- Main bronchus divides into secondary bronchi
- Right = 3 and Left = 2
- Supply each lobe of the lungs
Describe the tertiary/segmental bronchi.
- Secondary bronchi divide into tertiary bronchi
- Right = 10 and Left = 9
- Supply each segment of the lung
- Segments are subdivisions of the lobes of the lung
What impact does the secretion of surfactant by cells in the alveoli have?
prevent surface tension effects
What is collateral ventilation?
Alveoli can be ventilated by channels which bypass the normal route of airways
- Channels of Martin
- Canals of Lambert
- Pores of Kohn
Channels of Martin.
bronchiole-bronchiole
Canals of Lambert.
bronchiole-alveolar
Pores of Kohn.
- Alveolar-alveolar
- Adult alveolus has ~5-20 pores
- Not present in infants under 1 year
What are the (3) components of the mucociliary transport system (defence)?
- Cilia
- Aqueous (sol) layer
- Viscous (gel) layer
What is the role of cilia in the mucociliary transport system (defence)?
- Tips of cilia hook into the gel layer to sweep it towards laryngopharynx
- Cilia beat in a coordinated fashion at 20 cycles per second, which can propel mucus at a rate of 2cm/min
What is the role of aqueous (sol) layer in the mucociliary transport system (defence)?
- Serous fluid which bathes the cilia
- Ciliary movement is impaired with increased and decreased levels of fluid
What is the role of the viscous (gel) layer in the mucociliary transport system (defence)?
- Made of mucous secreted from goblet cells
- Goblet cells produce 10-100ml mucus per day
- Foreign particles, cellular debris and microbes become trapped
What lobes are the lungs divided into?
Right lung = 3:
- Upper / superior
- Middle
- Lower / inferior
Left lung = 2:
- Upper / superior
- Lower / inferior
(Smaller due to position of heart)
What are the lobes of the lungs divided by?
fissures
- Right = oblique + horizontal
- Left = oblique
What is the parietal pleura?
Lines the inner surface of the thoracic wall and superior surface of the diaphragm
What is the visceral pleura?
Covers the outer surface of the lungs and lines the fissures
What is the purpose of the pleural fluid?
- Acts as a lubricant allowing the layers to glide over each other during inspiration and expiration
- Increases surface tension ‘locks’ 2 pleural layers together
True Ribs.
- Pairs 1-7
- Articulate with vertebra and directly with sternum (via costal cartilage)
False Ribs.
- Pairs 8-10
- Articulate with vertebra and indirectly with sternum (via costal cartilage of ribs 6 and 7)
How many pairs of ribs are there?
12
What are the (3) elements of the sternum?
- Manubrium
- Body
- Xiphoid process
What bones articulate at the sternocostal joints?
Joints between ribs 1-7 (true ribs) & sternum
What type of joint is it between the manubrium and 1st rib?
fibrocartilaginous joint
Which ribs are surrounded by thin capsules?
Ribs 2-7
What muscles produce inspiration?
- Diaphragm
- External intercostals
What are the accessory muscles of inspiration?
- Sternocleidomastoid
- Scalenes
- Pec minor + pec major
What muscles produce forced expiration?
- Internal intercostals
- Rectus abdominis
- Transversus abdominis
- Internal + external obliques
What are the origins of the diaphragm?
Costal part: lower margin of costal arch (inner surface ribs 7-12)
Lumbar part:
- Medial: L1-L3 vertebral bodies and intervertebral discs (2nd and 3rd), anterior longitudinal ligament
- Lateral: arcuate ligaments (median, medial and lateral)
Sternal part: posterior surface of xiphoid process
Where is the insertion of the diaphragm?
Central tendon
What is the innervation of the diaphragm?
Phrenic nerve (C3, C4, C5)
Is expiration an active or passive process?
mostly passive, but can be active too
Is inspiration an active or passive process?
active (requiring energy)
Breathing/respiration
a collective term for inspiration and expiration
What are (8) abnormal breathing patterns?
- Bradypnoea
- Hyperventilation/Tachypnoea
- Dyspnoea
- Apnoea
- Agonal breathing
- Orthopnoea
- Kussmaul respiration
- Cheyne-Stokes breathing
Accessory muscles of inspiration can assist what (2) things?
- Deep inspiration
- During episodes of respiratory distress
What can the use of accessory muscle of inspiration suggest?
a sign of respiratory distress
How does forced expiration occur?
- Contraction of the abdominal muscles: causes the abdominal contents to push up against the diaphragm (reduces the vertical diameter of the thorax)
- Contraction of the internal intercostals: depress the ribs and decrease space in the thorax
What is the pump handle biomechanics of breathing?
- Primarily involves upper ribs and sternum
- Increases the anterior-posterior dimension of the chest
What is the bucket handle biomechanics of breathing?
- Primarily involves the lower ribs
- Increases the transverse diameter of the chest
What are the interchondrial joints?
- Ribs 7-10 involved
- Synovial joints
- Occur between the costal cartilages of adjacent ribs
Floating ribs.
- Pairs 11-12
- Articulate with vertebra, no attachment anteriorly to sternum
Which ribs are typical?
2-9
Which ribs are atypical?
1, 10, 11 + 12
Where does ciliated epithelium line?
- Nasopharynx
- Pharynx
- Trachea
- Bronchi
- Bronchioles
What does ciliated epithelium contain?
- Goblet cells (secrete mucus)
- Cilia (microscopic hair like structures capable of rhythmic motion 1 of the 3 components of the MTS)
Why is the 10th rib atypical?
head of rib has 1 facet for articulation with 1 vertebral body (T10)
Why are the 11th & 12th ribs atypical?
- No anterior attachment to sternum
- Only articulate with 1 vertebral body (rib 11 = T11, rib 12 = T12)
- No tubercles
- Shorter than the other ribs
What ribs are involved in interchondrial joints?
ribs 7-10
What is the purpose of interchondrial joints?
provide anchorage to the sternum
What are the (3) key functions of the blood?
- Transport
- Regulation
- Protection
What does the blood transport around the body?
- Oxygen
- Metabolic waste products from cells to elimination site (lungs CO2, kidneys nitrogenous waste)
- Hormones (from endocrine organs to target organs)
How is the blood used for regulation?
- Body temperature
- pH in body tissues
- Maintaining adequate fluid volume
How does blood protect the body?
- Prevent blood loss (via clotting)
- Prevent infection (via antibodies + white blood cells)
What are the (4) main components of the blood?
- Plasma
- Erythrocytes (Red Blood Cells)
- Leukocytes (White Blood Cells)
- Platelets
What does platelets do in the blood?
form clots and stop or prevent bleeding
What is blood plasma?
– Carries platelets, red blood cells and white blood cells around the body
- Contains antibodies (known as immunoglobulins), which fight infection
What percentage of the blood is blood plasma?
approx. 55%
What is the name of the body cavity the heart is contained in?
Mediastinum
What is the name of the protective double membrane that surrounds the heart?
Pericardium
Where is the heart located?
- 1/3 lies to the right of the midline
- 2/3 lies to the left of the midline
(pyramid/cone shape - tilted)
What are the names of the (4) chambers of the heart?
- Right Atrium
- Left Atrium
- Right Ventricle
- Left Ventricle
What produces the “sound” of the heart beat?
closing of the valves
Where is the apex of the heart?
at the bottom (inferior) on the left border
(point of the heart)
Where is the base of the heart?
an imaginary line that travels diagonally across the heart (where the valves are)
What are the receiving chambers?
Atria
What are the pumping chambers?
Ventricles
What is the fibrous pericardium made of?
Tough fibrous connective tissue
What are the purposes of the fibrous pericardium?
- Protects heart
- Prevents overfilling
- Anchors heart to surrounding structures (including diaphragm via the central tendon)
Pericardium.
a double-walled sac surrounding the heart
Fibrous pericardium.
the outer layer of the pericardium
Serous pericardium.
the inner layer of the pericardium
What lines the fibrous pericardium?
Parietal pericardium
Parietal pericardium.
lines the fibrous pericardium
Visceral pericardium.
fused to external layer of the heart wall (epicardium)
Pericardial fluid.
in between the parietal and visceral pericardium - pericardial cavity
(lubricates and creates frictionless environment)
What are the (3) layers that compose the walls of the heart?
- Epicardium
- Myocardium
- Endocardium
Epicardium.
outer layer - a thin layer of external membrane
(visceral pericardium)
Myocardium.
Middle layer of cardiac muscle
- Thickest layer of the wall of the heart
- This layer contracts
- Composed of cardiac muscle fibres arranged in spirals and loops
- Separate systems for atria and ventricles
- Cardiac muscle cells (cardiomyocytes) are specialised “excitable cells”
Endocardium.
thin layer of endothelium
Why do atria have smaller + thinner walls than ventricles?
Only have to pump blood into the adjoining ventricle, but ventricles pump blood to the lungs + body
What are the names of the valves between the atrium & ventricles (Left/Right)?
Atrioventricular valves
Left = bicuspid vale (mitral valve)
Right = tricuspid valve
What are the names of the valves between the ventricles & arteries (Left/Right)?
Semilunar valves
Left = aortic valve
Right = pulmonary valve
Why do heart valves open & close?
pressure differences
Describe blood flow through the right side of the heart.
Pulmonary Circulation
- Right atrium receives deoxygenated blood from the body (via the superior and inferior vena cava)
- Blood passes through the right tricuspid valve into the right ventricle
- Then passes through the pulmonary valve into the pulmonary artery
Destination – lungs
Describe blood flow through the left side of the heart.
Systemic circulation
- Left atrium receives oxygenated blood from the lungs (via the pulmonary veins)
- Blood then passes through mitral valve into the left ventricle
- Though the aortic valve into the aorta
Destination – the body
Where are coronary arteries located?
in the epicardium (superficial)
(send branches deeper into the myocardium)
Coronary sinus.
Coronary veins return deoxygenated blood to the right atrium
Cardiac cycle.
mechanical events which occur with the flow of blood through the heart in one heartbeat
Describe the cardiac cycle & blood flow.
- Vena Cava (deoxygenated blood)
- Right Atrium
- Right Ventricle (via Tricuspid valve)
- Pulmonary arteries (via semilunar valves)
- Lungs
- Pulmonary veins (Oxygenated blood)
- Left Atrium
- Left Ventricle (via Bicuspid valve)
- Rest of the body
…Repeat…
Early diastole.
- Whole heart relaxed
- Pulmonary and aortic valves shut
- AV valves (tricuspid and bicuspid/mitral) open
- Blood flowing passively from great veins through atria to ventricles
Atrial systole.
- Atria contract forcing blood into the ventricles
- Atria then relax
Ventricular systole: isovolumetric contraction.
- Ventricles contract
- Increase ventricular pressure
- AV valves now close
- Aortic and pulmonary valves still closed – this contraction does not bring about any change in volume
Ventricular systole: ventricular ejection?
- Ventricular pressure continues to rise
- Aortic and pulmonary valves forced open
- Blood rapidly ejected into the aorta (L) and pulmonary artery (R)
Ventricular diastole: isovolumetric relaxation
- Ventricles relax and ventricular pressure drops
- Blood in aorta and pulmonary artery starts to flow back towards heart = aortic and pulmonary valves shut
What is the “Lub” sound in a heart beat?
sound of the AV valves closing
What is the “Dub” sound in a heart beat?
sound of the aortic + pulmonary valves closing
What are (4) specialised conduction fibres in the heart?
- Sinoatrial node (pacemaker)
- Atrioventricular node (AV node)
- Atrioventricular bundle of His
- Purkinje fibres
What does the sinoatrial node cause?
depolarisation + contraction of both atria (atrial systole)
What does the atrioventricular node cause?
- slows impulse down
- allows time for atrial contraction + ventricular filling
What is a normal adult heart rate?
50-100 bpm
What are (3) hormones released to increase heart rate?
- Catecholamines
- Adrenaline
- Noradrenaline
What are hormone released to decrease heart rate?
acetylcholine
What is normal adult blood pressure?
Systolic / Diastolic
95-140 / 60-90 mmHg
What is blood pressure?
pressure exerted by blood against the inner wall of an artery
How is blood pressure maintained?
- Heart rate
- Stroke volume
- Total peripheral resistance
How do we calculate blood pressure?
Blood pressure = Stroke volume X Heart rate X Total peripheral resistance
What is heart rate?
number of beats per minute
What is stroke volume?
volume of blood ejected from ventricles per contraction
What is cardiac output?
volume of blood ejected from ventricles in 1 minute (SV x HR)
What is total peripheral resistance?
friction encountered by blood as it passes through a peripheral artery
How is blood pressure regulated?
By baroreceptors located in pressure receptor zones:
- High pressure zones (e.g. aortic arch)
- Low pressure zones (e.g. venae cava, atria, pulmonary veins)
Renal system
- long term regulation via altering blood volume
How do baroreceptors cause adjustments to blood pressure?
Baroreceptors send signals to the medulla (in brainstem) where autonomic nervous system stimulation leads to adjustments
What should stroke volume be (approx.)?
approx. 70mL/beat
What happens to cardiac output during exercise?
increases due to higher heart rate
What is the primary function of the sinoatrial (SA) node in the heart?
to act as the pacemaker of the heart
Does the heart spend more time in diastole or systole?
Diastole
What is the primary purpose of coronary arteries?
to supply oxygenated blood to the myocardium
Describe Frank Starling law?
The greater the venous return, the greater the stroke volume
What is the name of the membrane that covers the surface of the lungs?
Viceral pleura
What is an accessory muscle of inspiration?
Sternocleidomastoid
What are channels for collateral ventilation of the lungs?
- Pores of Kohn
- Channels of Lambert
- Canals of Martin
Where does the diaphragm attach?
Xiphoid process
What is the primary function of lung surfactant?
reduce surface tension of the alveoli
Which part of the brain controls the basic rhythm of respiration?
Medulla oblongata
What does the mucociliary escalator primarily function to do?
move mucus + trapped particles out of the airways
What is the movement of the chest responsible for increasing the antero-posterior diameter of the chest?
pump-handle movement
What does the P-QRS-T complex represent?
the depolarisation + repolarisation of the atria + ventricles
What is microcirculation?
flow of blood from arteriole to venule through capillary bed
What are true capillaries?
actual exchange vessels
What is metarteriole?
thoroughfare channel connecting arteriole to venule (vascular shunt)
What is bulk flow?
where filtered blood plasma moves in & out of tissues via pressure + osmotic changes
What does the P wave of an ECG represent (on an ECG)?
atrial depolarisation
What does the QRS complex represent (on an ECG)?
ventricular depolarisation + therefore contraction (via bundle of His + Purkyne fibres)
What does the Q wave represent (on an ECG)?
depolarisation of septum
What does the R wave represent (on an ECG)?
depolarisation of ventricles
What does the S wave represent (on an ECG)?
depolarisation of Purkyne fibres
What does the T wave represent (on an ECG)?
ventricular repolarisation + relaxation
What is Inspiratory Capacity made up of?
- Inspiratory Reserve Volume
- Tidal Volume
What is Functional Residual Capacity made up of?
- Expiratory Reserve Volume
- Residual Volume
What is Vital Capacity made up of?
- Inspiratory Reserve Volume
- Tidal Volume
- Expiratory Reserve Volume
What is Total Lung Capacity made up of?
- Inspiratory Reserve Volume
- Tidal Volume
- Expiratory Reserve Volume
- Residual Volume
