regulation of blood gases and blood pressure hbs3a
TRANSCRIPT
Regulation of blood gases and blood pressure
HBS3A
Regulation of blood gases
The body needs a constant supply of o_________ in order to
Carbon dioxide (produced in r________________) must be constantly removed because
The two systems involved in control of the blood gases are the c___________________ and r__________________ systems
Regulation of blood gases
The body needs a constant supply of oxygen in order to maintain respiration
Carbon dioxide (produced in respiration) must be constantly removed because it is toxic, and it alters the pH of blood
The two systems involved in control of the blood gases are the cardiovascular and respiratory systems
Blood gases
Oxygen can travel in the blood dissolved in plasma but mostly travels attached to h______________, in red blood cells.
Carbon dioxide travels in the blood dissolved in plasma, attached to haemoglobin, in r____ b______ cells, but mostly as _________________ ions and ________________________ ions.
This is due to the reaction:
carbon dioxide + water __________ ___________ + __________
Blood gases
Oxygen can travel in the blood dissolved in plasma but mostly travels attached to haemoglobin, in red blood cells.
Carbon dioxide travels in the blood dissolved in plasma, attached to haemoglobin, in red blood cells, but mostly as hydrogen ions and hydrogen carbonate (bicarbonate) ions.
This is due to the reaction:
carbon dioxide + water H2CO3 H+ + HCO3-
Respiratory control systems
Respiratory control systemsChemoreceptors in the medulla detect levels of ___________________
in the blood. These are most sensitive to changes in ____________ and are responsible for _____% of the change in breathing rate. This response is s_________
Chemoreceptors in the carotid and aortic bodies detect levels of ______ in the blood. These are most sensitive to changes in _____________ and are responsible for _____% of the change in breathing rate. This response is f_________
There is interaction between oxygen, carbon dioxide and pH and all contribute to changes in the breathing rate, but the most sensitivity is to _____________________________________
These chemoreceptors send information to the respiratory centre of the m__________, which (along with other areas) controls the activity of the respiratory system.
Voluntary control can by-pass the respiratory centre.
Respiratory control systemsChemoreceptors in the medulla detect levels of CO2, H+ and O2 in the
blood. These are most sensitive to changes in CO2 and H+ and are responsible for 70 – 80 % of the change in breathing rate. This response is slow
Chemoreceptors in the carotid and aortic bodies detect levels of CO2, H+ and O2 in the blood. These are most sensitive to changes in CO2 and H+ and are responsible for 20 – 30 % of the change in breathing rate. This response is fast
There is interaction between oxygen, carbon dioxide and pH and all contribute to changes in the breathing rate, but the most sensitivity is to H+ and CO2
These chemoreceptors send information to the respiratory centre of the medulla, which (along with other areas) controls the activity of the respiratory system.
Voluntary control can by-pass the respiratory centre.
CO2 increases
CO2 levels _________ Chemoreceptors in medulla
respiratory muscles_____________
Respiratory centre in medulla
breathing rate _________
pH _______________
Chemoreceptors in aorta and carotid bodies
breathing rate decreases
The level of blood gases is controlled by a negative feedback system:
Negative feedback
CO2 increases
CO2 levels drops Chemoreceptors in medulla
respiratory musclesIncrease activity
Respiratory centre in medulla
breathing rate increases
pH decreases
Chemoreceptors in aorta and carotid bodies
breathing rate decreases
The level of blood gases is controlled by a negative feedback system:
Negative feedback
Changes in blood gases
Hyperventilation is
It can cause levels of carbon dioxide to fall.
This can cause
During exercise carbon dioxide production _________________ and oxygen consumption _________________________ so the breathing rate will _____________________________
Changes in blood gases
Hyperventilation is rapid shallow breathing to blow off carbon dioxide
It can cause levels of carbon dioxide to fall. This can cause decrease a decrease in carbon dioxide that
is so great, that there is no longer any stimulation to breath, so you stop breathing & fall unconscious. After a time unconscious, the carbon dioxide levels rise & you breath again. The problem is if you are swimming, you will start to breath under water & drown, or if you have hurt yourself when falling unconscious (ie falling off a bridge, etc)
During exercise carbon dioxide production increases and oxygen consumption increases so the breathing rate will increase
Feedback control of breathing
Stimulus
Negative feedback Receptor
Response Modulator
Effector
Increased carbon dioxide
Feedback control of breathing
Stimulus
Negative feedback Receptor
Response Modulator
Effector
Increased carbon dioxide Decreased pH Decreased oxygen Chemoreceptors –
medulla and aortic and carotid bodies
Respiratory centremedulla
Respiratory muscles – diaphragmand intercostals
Increased breathing rate
Decreased carbon dioxide
Feedback control of breathing 2
Stimulus
Negative feedback Receptor
Response Modulator
Effector
Decreased carbon dioxide
Feedback control of breathing 2
Stimulus
Negative feedback Receptor
Response Modulator
Effector
Decreased carbon dioxideIncreased pHIncreased oxygen Chemoreceptors –
medulla and aortic and carotid bodies
Respiratory centremedulla
Respiratory muscles – diaphragmand intercostals
Decreased breathing rate
Increased carbon dioxide
Cardiovascular control systems
Define heart rate
Define stroke volume
Define cardiac output
Cardiac output can be calculated by
(CO = )
Define venous return
It depends on
Define blood pressure
It depends on
Cardiovascular control systems
Define heart rate - (HR) beats per minute
Define stroke volume - (SV) volume of blood leaving the heart each beat
Define cardiac output - (CO) volume of blood leaving the heart each minute
Cardiac output can be calculated by multiplying heart rate by stroke volume(CO = SV x HR)
Define venous return – volume of blood returning to the heart
It depends on cardiac output and muscle activity
Define blood pressure – (BP) force with which the blood presses on the walls of blood vessels
It depends on cardiac output and diameter of blood vessels
The heart
Control of the heartThe pacemaker (sino-atrial node or SA node) is found and is responsible
The activity of the heart is controlled by the m___________, by means of the s____________ and p___________________ nervous systems.
Fibres from both systems run down the spinal cord as part of the cardiac nerves to the cardiac muscle of the atria in the heart and the sino-atrial and atrio-ventricular nodes.
The cardiac muscle of the ventricles get mainly the s____________________
The sympathetic fibres release n__________________ and cause
The parasympathetic fibres release a____________________ and cause
Control of the heartThe pacemaker (sino-atrial node or SA node) is found in the wall of the
right atrium just below the superior vena cavaand is responsible for the rhythmical contractions of the heart
The activity of the heart is controlled by the medulla, by means of the sympathetic and parasympathetic nervous systems.
Fibres from both systems run down the spinal cord as part of the cardiac nerves to the cardiac muscle of the atria in the heart and the sino-atrial and atrio-ventricular nodes.
The cardiac muscle of the ventricles get mainly the sympathetic fibres
The sympathetic fibres release noradrenaline and cause increased heart rate and stroke volume
The parasympathetic fibres release acetylcholine and cause decreased heart rate and force of contraction
Control of the heart
Autonomic control is balancing opposing effects of the sympathetic and parasympathetic systems.
At rest, p___________________________ activity is dominant.
During exercise, s____________________ activity increases.
Other influences on heart rate and stroke volume include
Control of the heart
Autonomic control is balancing opposing effects of the sympathetic and parasympathetic systems.
At rest, parasympathetic activity is dominant.
During exercise, sympathetic activity increases.
Other influences on heart rate and stroke volume include temperature, blood pressure, age, sex and emotional state
Control of the heart 2
The cardiovascular regulating centre controls
The three main influences on stroke volume are:length of diastole – this influences
venous return – thisand is influenced by activity of s_____________ muscles,
r_______________ movements, tone of v___________ and
sympathetic nervous system – this causes
Control of the heart 2
The cardiovascular regulating centre controls heart rate, stroke volume and blood pressure
The three main influences on stroke volume are:length of diastole – this influences stroke volume as it
affects how much blood can enter the heart
venous return – this affects stroke volume and is influenced by activity of skeletal muscles, respiratory movements, tone of veins and ease of blood flow through arterioles in the muscles
sympathetic nervous system – this causes increased stroke volume and heart rate
Control of the heart 2
Other factors that affect heart rate include
age –
sex –
emotional state –
During exercise heart rate, stroke volume and blood pressure will tend to rise due to
Control of the heart 2
Other factors that affect heart rate includeage – HR is fastest at birth and slows as we age
sex – males have a slower HR than females
emotional state – strong emotions eg fear, anger, anxiety increase HR, depression & grief lower HR
During exercise heart rate, stroke volume and blood pressure will tend to rise due to increased sympathetic activity, increased muscle and respiratory movements, increased temperature and effects of adrenaline and noradrenaline
Ventricular f_________
Venous r_________
Length of d_________
Strength of c___________
N_________________
Heart rate
A_________________ nervous system
Stroke volume
Degree of stretch of h_______ m_______
Cardiac output
A___________ nervous system
T__________
A___________
Factors affecting cardiac output
Ventricular filling
Venous return
Length of diastole
Strength of contraction
Noradrenaline
Heart rate
Autonomic nervous system
Stroke volume
Degree of stretch of heart muscle
Cardiac output
Autonomic nervous system
Temperature
Adrenaline
Factors affecting cardiac output
D__________ in sympathetic andi___________ in parasympathetic output
Cardiovascular regulating centre in m____________ oblongata
Vaso_______D__________ cardiac output
D________ in blood pressure
Pressoreceptors send m________ impulses
Arteries stretch m_______
Rising blood pressure
Vaso_________ I__________ cardiac output
I___________ in sympathetic andd_____________ in parasympathetic output
I__________ in blood pressure
Falling blood pressure
Arteries stretch l_______
Pressoreceptors send f________ impulses
Factors affecting blood pressure
Decrease in sympathetic andincrease in parasympathetic output
Cardiovascular regulating centre in medulla oblongata
VasodilationDecreased cardiac output
Decrease in blood pressure
Pressoreceptors send more impulses
Arteries stretch more
Rising blood pressure
Vasoconstriction Increased cardiac output
Increase in sympathetic anddecrease in parasympathetic output
Increase in blood pressure
Falling blood pressure
Arteries stretch less
Pressoreceptors send fewer impulses
Factors affecting blood pressure
Blood flowDefine vasodilation -
Describe factors that increase vasodilation
Define vasoconstriction –
Describe factors that increase vasoconstriction
Blood flowDefine vasodilation - widening of blood vessels (arterioles) to increase
blood flow
Describe factors that increase vasodilation • sympathetic system to muscles and heart• wastes eg carbon dioxide and lactic acid• Adrenaline (muscle and heart)
Define vasoconstriction - narrowing of blood vessels (arterioles) to decrease blood flow
Describe factors that increase vasoconstriction • sympathetic system to abdominal organs• Adrenaline (abdominal organs)
Receptors
How are the following receptors involved in the regulation of the cardiovascular system?
Thermoreceptors
Chemoreceptors
Mechanoreceptors
Pressoreceptors
ReceptorsHow are the following receptors involved in the regulation of the
cardiovascular system?Thermoreceptors – detect heat – increased temperature stimulates
increased breathing rate which increases venous return, increased heart rate and vasodilation of blood vessels near the skin
Chemoreceptors – detect concentrations of carbon dioxide, oxygen and pH – these affect breathing rate which affects venous return, and heart rate
Mechanoreceptors – detect movement of muscles and joints during exercise – increased movement stimulates increased breathing rate which increases venous return, increased heart rate and release of adrenal hormones
Pressoreceptors – detect blood pressure – changes in blood pressure stimulates changes in sympathetic and parasympathetic output, changing cardiac output and degree of vasodilation
Blood pressure
Describe factors that increase blood pressure
Describe factors that decrease blood pressure
Blood pressure
Describe factors that increase blood pressure • Increased force of contraction• Vasoconstriction or narrowing of blood vessels (eg
arteriosclerosis)• Increased cardiac output
Describe factors that decrease blood pressure
• Decreased force of contraction• Vasodilation of blood vessels• Decreased cardiac output • Reduced blood volume (eg loss of blood)