Presentation is loading. Please wait.

Presentation is loading. Please wait.

Regulation of blood gases and blood pressure HBS3A.

Similar presentations


Presentation on theme: "Regulation of blood gases and blood pressure HBS3A."— Presentation transcript:

1 Regulation of blood gases and blood pressure HBS3A

2 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

3 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

4 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 __________ ___________ + __________

5 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 H 2 CO 3 H + + HCO 3 -

6 Respiratory control systems

7 Chemoreceptors 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.

8 Respiratory control systems Chemoreceptors in the medulla detect levels of CO 2, H + and O 2 in the blood. These are most sensitive to changes in CO 2 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 CO 2, H + and O 2 in the blood. These are most sensitive to changes in CO 2 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 CO 2 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.

9 CO 2 increases CO 2 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

10 CO 2 increases CO 2 levels drops Chemoreceptors in medulla respiratory muscles Increase 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

11 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 _____________________________

12 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

13 Feedback control of breathing Stimulus Negative feedbackReceptor ResponseModulator Effector Increased carbon dioxide

14 Feedback control of breathing Stimulus Negative feedbackReceptor ResponseModulator Effector Increased carbon dioxide Decreased pH Decreased oxygen Chemoreceptors – medulla and aortic and carotid bodies Respiratory centre medulla Respiratory muscles – diaphragm and intercostals Increased breathing rate Decreased carbon dioxide

15 Feedback control of breathing 2 Stimulus Negative feedbackReceptor ResponseModulator Effector Decreased carbon dioxide

16 Feedback control of breathing 2 Stimulus Negative feedbackReceptor ResponseModulator Effector Decreased carbon dioxide Increased pH Increased oxygen Chemoreceptors – medulla and aortic and carotid bodies Respiratory centre medulla Respiratory muscles – diaphragm and intercostals Decreased breathing rate Increased carbon dioxide

17 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

18 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

19 The heart

20 Control of the heart The 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

21 Control of the heart The pacemaker (sino-atrial node or SA node) is found in the wall of the right atrium just below the superior vena cava and 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

22 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

23 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

24 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 – this and is influenced by activity of s_____________ muscles, r_______________ movements, tone of v___________ and sympathetic nervous system – this causes

25 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

26 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

27 Control of the heart 2 Other factors that affect heart rate include age – 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

28 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

29 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

30 D__________ in sympathetic and i___________ 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 and d_____________ in parasympathetic output I__________ in blood pressure Falling blood pressure Arteries stretch l_______ Pressoreceptors send f________ impulses Factors affecting blood pressure

31 Decrease in sympathetic and increase in parasympathetic output Cardiovascular regulating centre in medulla oblongata Vasodilation Decreased cardiac output Decrease in blood pressure Pressoreceptors send more impulses Arteries stretch more Rising blood pressure Vasoconstriction Increased cardiac output Increase in sympathetic and decrease in parasympathetic output Increase in blood pressure Falling blood pressure Arteries stretch less Pressoreceptors send fewer impulses Factors affecting blood pressure

32 Blood flow Define vasodilation - Describe factors that increase vasodilation Define vasoconstriction – Describe factors that increase vasoconstriction

33 Blood flow Define 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)

34 Receptors How are the following receptors involved in the regulation of the cardiovascular system? Thermoreceptors Chemoreceptors Mechanoreceptors Pressoreceptors

35 Receptors How 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

36 Blood pressure Describe factors that increase blood pressure Describe factors that decrease blood pressure

37 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)


Download ppt "Regulation of blood gases and blood pressure HBS3A."

Similar presentations


Ads by Google