Cardiovascular System Flashcards
Cardiovascular system
consists of blood vessels, heart, blood, pulmonary and system circulations
Hematopoletic stem cells
produce red & white blood cells and platelets
Characteristics of blood vessels
Function
Pressure
Lumen diameter
Wall thickness
Wall layers
Connective tissue
Valves
Layers of blood vessels
INNER: TUNICA INTIMA (endothelium
MIDDLE: Tunica Media
OUTER: Tunica Adventitia
Vasoconstriction vs vasovalidation
Blood Flow, Blood Pressure, and Resistance
*Stiffening of arteries→increased resistance→higher pressure→ reduced flow→increased workload
*mmHg systolic: Pressure exerted when blood is ejected into arteries (any higher than 120 and it loses its ability to contract)
*mmHg diastolic: Pressure blood exerts within arteries between heartbeats (any higher than 80 and it loses its ability to expand)
Lower risk of CVD
* Fueled by aninflammatory response
* LDL cholesterol accumulation also further stimulates
body’s defense system
* May narrow the arterY which reduces blood flow
* Blood clots→thrombus, embolus
* Treated with blood thinning or blood dissolving drugs
Aneurysm
most common place to have it in the aorta, has various causes
High blood pressure can cause it
Ischemic Heart disease
- Also called coronary artery disease
- Fatty deposits occur in the coronary arteries that normally nourish heart muscle
- Angina pectoris serves as a warning sign
- Imbalance between myocardial blood supply and demand
Symptoms of ischemic heart disease
- chest pain / tightness / heaviness
- unusual shortness of breath
- unusual fatigue
- unexpected sweating
- unexplained weakness
- Discomfort in the neck, jaw, teeth or back
- Nausea
- Stabbing pain instead of
chest pressure - Stomach (abdominal) pain
Gender bias and cardiovascular disease
Estrogen, menopause and pregnancy ( to look this up)
Framingham heart study
- Started in 1948 by the U.S. Public Health Service→5,209 participants in the town of Framingham, MA, USA
- To understand the natural history of CVD and identify their major causal factors
- The ‘crown jewel’ of epidemiology
Who is at risk for cardiovascular disease
Cigarette smoking
Cholesterol (Totl cholesterol, LDL cholesterol)
Hypertension ( High blood pressure)
Age, sex
Typer 2 Diabetes
Overweight or Obesity ( BMI : KG/M^20
Who should screen for high cholesterol
Men and women post-menopausal ( or over 40 years - inclusive of the forty years)
Treating Ischemic Heart Disease
Medication, surgery - coronary bypass graft surgery
Rehabilitation programs after cardiac problem: * Take charge of their medical condition
* Develop strategies to improve risk factors for CVD
* Maintainanexerciseprogramtoimprovehealthandwellbeing
* Incorporate healthy food choices and practices
* Develop strategies to manage their psychosocial risks for CVD
Exercise
Physical activity:
* Any bodily movement produced by skeletal muscles resulting in an increase over resting energy expenditure
* Execise:* Planned
* Structured
* Repetitive
Heart rate
- Estimated max heart rate=220-age(in years)
- Moderate intensity: 50-75% of heart rate maximum * High intensity: >75% of heart rate maximum
Rating of perceived exertion 0-10
- Moderate intensity: 3-7
- High Intensity: >7
Current Recommendations
- 150 minutes per week of moderate intensity exercise or physical activity
- Strengthening exercises 2 times per week
- 75 minutes per week of high intensity exercise or physical activity
- Strengthening exercises 2 times per week
- How do these recommendations differ for individuals affected by a disability?
Energy systems in exercise
- Phosphagen system (or ATP-phosphocreatine)
* 2. Anaerobic system (glycolytic)
* 3. Aerobic system (oxidative)
Outline of exercise
- How they work
- Major fuel source
- Rate/capacity
- Muscle fibre types
- How to improve rate/capacity
Energy systems: Phosphagen System
- ATP→ADP through the enzyme ATPase * Produces energy
- ADP→ATP through the enzyme Creatine Kinase * Adds a phosphate group back to ADP
- Rate = very fast
- Capacity = limited
Phosphagen System: Type IIx Muscle Fibres
- Type IIx (fast glycolytic) muscle fibres * Fast contraction
- Limited oxygen use
- Few mitochondria, capillaries
- High amounts of glycogen
- Best ability to regenerate ATP * Highly fatigable
- Uses glycogen as energy
- Net output of 2 or 3 ATP molecules
- Rate = fast
- Capacity = limited (less limited than phosphagen system)
Energy Systems: Anaerobic System
Anaerobic System: Type IIx Muscle Fibres
- Type IIx (fast glycolytic) muscle fibres * Fast contraction
- Limited oxygen use
- Few mitochondria, capillaries
- High amounts of glycogen
- Best ability to regenerate ATP * Highly fatigable
- Maximum amount of force that a muscle or muscle group can exert during a single, maximal effort contraction
- Often measured with a one-repetition maximum isotonic contraction (i.e. maximum amount of weight that can be lifted with a single contraction)
- Muscle tissue= best calorie burning tissue
- Greater muscle mass= greater basal metabolic rate
need to engage in resistance training
Muscular Strength
Progressive overload
- Increasing the intensity of exercise over a period of time
- Why is it needed?
- Muscle will adapt quickly to receiving a constant stimuli
- How can this be done?
- Increase the resistance of the exercise (e.g. add more weight)
- Add volume (i.e. number of sets or repetitions)
- Perform the movement with more control (e.g. greater range
of motion or slow the movement down)
Energy Systems: Aerobic system
- Uses oxygen as energy supply
- Net output of 32 or 33 ATP molecules
- Rate = very, very slow
- Capacity = unlimited
- Moderate oxygen supply to meet energy demands of skeletal muscle
- Type IIa (fast oxidative) muscle fibres * Fast contraction
- Uses oxygen
- Some mitochondria, capillaries
- Moderate amounts of glycogen
- Can regenerate ATP
- Moderately fatigue resistant
Aerobic Exercise: Type IIa Muscle Fibres
- Sufficient oxygen supply to meet energy demands of skeletal muscle
- Type I (slow oxidative) muscle fibres
- Slow contraction
- Use oxygen
- Lots of mitochondria, capillaries
- Low amounts of glycogen
- Low ability to regenerate ATP
- Fatigue resistant
Aerobic Exercise: Type I Muscle Fibres
Aerobic Exercise: Cardiorespiratory Fitness
- Purpose
- To improve cardiorespiratory fitness (CRF)
- CRF
- efficiency of muscle to use oxygen to produce energy
in skeletal muscle - Used as a predictor for heart transplant
- Also known as VO2max or VO2peak
- Units: ml of O2 per kilogram of body mass per minute of consumption
- Improve CRF through a combination of high and moderate intensity aerobic exercise
Beneficial Adaptations to Exercise
- Increased number of adenosine receptors
- Increased capillary network
- Increased stroke volume
- Increased recruitment of glucose transporters to skeletal muscle cell membrane
to study
Adenosine Receptors: Vasculature
Adenosime Receptors: Central Nervous System
Increased Capillary Density
Increased Stroke Volume
Elevated Heart Rate: Hypertrophic Cardiomyopathy
Increased Recruitment of Glucose Transporters
Increased stroke volume
- Conditions of exercise environment
- Elevated heart rate
- Increased blood flow demand to and away from skeletal muscle
- Adaptation
- Heart ejects more blood with each
contraction - Less strain on the heart
Example of impact muscle strength
Exercise is Medicine: Muscle Strength and Mortality
* López-Bueno R et al. 2022
* 7 year follow up
* 54 thousand men, 66 thousand women (average age: 64 years)
* Increased muscle strength was associated with a 60% reduced risk of mortal
55
Exercise is Medicine: Muscle Strength and COVID-19
* Gil S et al. 2021
* 93 males, 93 females
* Monitored during hospitalization for moderate to severe COVID-19
* Increased muscle strength and mass was associated with 2-3 days shorter hospital stay compared to those with the lowest muscle strength and mass
Exercise is Medicine: Physical Activity and Blood Glucose
* Buffey AJ et al. 2022
* Prolonged sitting (≥5 hours)
* Interrupted with standing or light intensity walking for 2- 30 minutes
Tips on exercise if you sit for very long
- Interruptions in sitting occurred every 20-60 minutes
- Standing and light intensity walking reduced blood
glucose, improved insulin sensitivity - Stronger effect of light intensity walking compared to standing
Exercise is medicine: Physical Activity and Muscle Protein Synthesis
- Moore DR et al. 2022
- Prolonged sitting (7.5 hours)
- Interrupted with light intensity walking (2 mins at 3.1mph) or 15 body weight squats
- Interruptions in sitting occurred every 30 minutes
- Rate of muscle protein synthesis was higher with “activity snacks” compared to sitting
