17.4 Evaluate Nutritional Strategies to Impact Gastrointestinal Wellness
3 min read•june 18, 2024
The cardiac cycle is a complex dance of contractions and relaxations that keep our blood flowing. From atrial systole to ventricular diastole, each phase plays a crucial role in pumping oxygen-rich blood throughout our bodies and returning deoxygenated blood to the lungs.
Blood flow dynamics are governed by pressure gradients and resistance in our cardiovascular system. Factors like blood vessel diameter and tissue metabolic demands influence how blood moves through our bodies, ensuring that active tissues receive the oxygen and nutrients they need to function properly.
Cardiac Cycle and Hemodynamics
Phases of cardiac pumping action
Top images from around the web for Phases of cardiac pumping action
Cardiac Cycle · Anatomy and Physiology View original
Is this image relevant?
Cardiac Cycle · Anatomy and Physiology View original
Is this image relevant?
Cardiac cycle - Wikipedia View original
Is this image relevant?
Cardiac Cycle · Anatomy and Physiology View original
Is this image relevant?
Cardiac Cycle · Anatomy and Physiology View original
Is this image relevant?
1 of 3
Top images from around the web for Phases of cardiac pumping action
Cardiac Cycle · Anatomy and Physiology View original
Is this image relevant?
Cardiac Cycle · Anatomy and Physiology View original
Is this image relevant?
Cardiac cycle - Wikipedia View original
Is this image relevant?
Cardiac Cycle · Anatomy and Physiology View original
Is this image relevant?
Cardiac Cycle · Anatomy and Physiology View original
Is this image relevant?
1 of 3
- Systole: period of contraction
- Atrial systole: atria contract, forcefully pumping remaining blood into ventricles (80% of ventricular filling occurs passively during ventricular diastole)
- Ventricular systole: ventricles contract, pumping oxygen-poor blood into pulmonary artery (right ventricle) and oxygen-rich blood into aorta (left ventricle)
- Diastole: period of relaxation
- Atrial diastole: atria relax and fill with blood from veins (superior and inferior vena cava fill right atrium; pulmonary veins fill left atrium)
- Ventricular diastole: ventricles relax and fill with blood from atria, allowing for 80% of ventricular filling
Key events in cardiac cycle
- Atrial systole
- Atria contract, pumping remaining blood into ventricles (20% of ventricular filling)
- AV valves (tricuspid and mitral) open, allowing blood flow from atria to ventricles
- Ventricular systole
- Ventricles contract, pumping blood into pulmonary artery (right ventricle) and aorta (left ventricle)
- AV valves close, preventing backflow of blood into atria (first heart sound, S1, "lub")
- Semilunar valves (pulmonary and aortic) open, allowing blood flow into arteries
- Ventricular diastole
- Ventricles relax and fill with blood from atria (80% of ventricular filling occurs passively)
- Semilunar valves close, preventing backflow of blood into ventricles (second heart sound, S2, "dub")
- AV valves open, allowing blood flow from atria to ventricles
- Atrial diastole
- Atria relax and fill with blood from veins (superior and inferior vena cava fill right atrium; pulmonary veins fill left atrium)
- Blood flows passively from atria to ventricles through open AV valves due to pressure gradient
Blood flow dynamics in cardiovascular system
- Blood flow () determined by relationship between pressure gradient () and resistance ()
- Increased pressure gradient leads to increased blood flow (e.g., during ventricular systole)
- Increased resistance leads to decreased blood flow (e.g., in narrowed or constricted blood vessels)
- Pressure gradient: difference in pressure between two points in cardiovascular system
- Pressure highest in aorta, decreases as blood flows through systemic circulation (arteries, arterioles, capillaries, venules, veins)
- Pressure lowest in vena cava, increases as blood returns to heart
- Resistance factors: blood vessel diameter, blood viscosity, total vessel length
- Vasoconstriction (narrowing of blood vessels) increases resistance, decreases blood flow
- Vasodilation (widening of blood vessels) decreases resistance, increases blood flow
- Autoregulation: local tissues adjust blood flow to meet metabolic demands
- Metabolically active tissues (e.g., exercising skeletal muscle) release vasodilators (e.g., nitric oxide) to increase blood flow
- Less active tissues (e.g., resting skeletal muscle) experience vasoconstriction to decrease blood flow, conserving energy and redirecting blood to active tissues
Cardiac Performance Factors
- Preload: the volume of blood in the ventricles at the end of diastole, influencing initial muscle stretch
- Afterload: the pressure that the ventricles must overcome to eject blood, affected by arterial blood pressure
- Stroke volume: the amount of blood ejected from the ventricle during one contraction
- Ejection fraction: the percentage of blood ejected from the ventricle during one contraction compared to its end-diastolic volume
- Frank-Starling law: describes how the heart naturally adapts to changes in blood volume, increasing stroke volume as preload increases
- Cardiac output: the volume of blood pumped by the heart in one minute, calculated by multiplying stroke volume by heart rate
Key Terms to Review (27)
24-Hour Dietary Recall: A 24-hour dietary recall is a method of dietary assessment where an individual is asked to recall and report all the food and beverages they consumed in the previous 24-hour period. This technique provides a detailed snapshot of an individual's recent dietary intake and is commonly used in nutrition research and clinical practice to evaluate nutritional status and guide dietary interventions.
Anti-Inflammatory Diet: An anti-inflammatory diet is a dietary approach that focuses on consuming foods with anti-inflammatory properties to help reduce inflammation in the body. This type of diet is often recommended to support various health conditions, including pulmonary, gastrointestinal, and musculoskeletal disorders, where inflammation plays a key role.
Bile Acids: Bile acids are a group of steroid-based compounds produced in the liver and secreted into the bile. They play a crucial role in the digestion and absorption of fats, as well as the regulation of gastrointestinal wellness.
Bioavailability: Bioavailability refers to the degree and rate at which a substance, such as a nutrient or medication, is absorbed and becomes available for use or storage in the body. It is a crucial concept that connects the consumption of nutrients, minerals, and supplements to their ultimate impact on physiological processes and health outcomes.
Bloating: Bloating refers to a feeling of fullness, tightness, or discomfort in the abdominal area, often accompanied by increased gas or distension. It is a common gastrointestinal issue that can impact overall digestive wellness and comfort.
Constipation: Constipation is a condition characterized by infrequent or difficult bowel movements, often accompanied by hardened stool and discomfort. It is a common gastrointestinal issue that can have significant impacts on overall health and wellness when not properly addressed through nutritional strategies.
Crohn's Disease: Crohn's disease is a chronic, inflammatory bowel disease that can affect any part of the gastrointestinal tract, most commonly the end of the small intestine (the ileum) and the beginning of the colon. It is characterized by periods of flare-ups and remission, and can significantly impact the body's ability to digest and absorb nutrients, leading to various nutritional and digestive complications.
Digestive Enzymes: Digestive enzymes are specialized proteins produced by the body that catalyze the breakdown of food into smaller, absorbable molecules. They play a crucial role in the digestive system's ability to effectively process and utilize the nutrients from the foods we consume.
Elimination Diet: An elimination diet is a methodical process of temporarily removing certain foods or food groups from the diet to identify potential food sensitivities or allergies that may be contributing to gastrointestinal symptoms or other health issues. This approach is commonly used to assess and manage gastrointestinal wellness.
Enteral Nutrition: Enteral nutrition refers to the delivery of nutrients directly into the gastrointestinal tract, typically through a feeding tube. It is a method of providing nourishment to individuals who are unable to meet their nutritional needs through oral intake alone.
Fiber: Fiber refers to the indigestible parts of plant-based foods that pass through the human digestive system without being broken down. It plays a crucial role in maintaining gut health, managing chronic conditions, and promoting overall wellness.
FODMAP Diet: The FODMAP diet is a nutritional approach that focuses on the management of gastrointestinal symptoms by limiting the intake of specific types of carbohydrates known as FODMAPs (Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols). This diet is commonly used to help individuals with conditions like irritable bowel syndrome (IBS) and other functional gastrointestinal disorders manage their symptoms.
Food Frequency Questionnaire: A food frequency questionnaire (FFQ) is a tool used in nutrition research and population health assessments to evaluate an individual's or a group's usual dietary intake over a specified period of time. It is a comprehensive survey that asks about the frequency of consumption of various food items, allowing researchers to estimate nutrient intake and dietary patterns.
Gastric Acid: Gastric acid is a digestive fluid produced in the stomach that is essential for the breakdown and digestion of food. It is a key component of the gastric juice and plays a crucial role in maintaining gastrointestinal wellness and facilitating various treatments related to the digestive system.
Glutamine: Glutamine is a non-essential amino acid that plays a crucial role in various physiological processes, particularly in relation to gastrointestinal wellness and chronic gastrointestinal illnesses. As a key nutrient, glutamine is essential for maintaining the integrity and function of the gastrointestinal tract, making it an important consideration in nutritional strategies to impact and evaluate gastrointestinal wellness.
Gut Motility: Gut motility refers to the coordinated contractions and relaxations of the smooth muscles in the gastrointestinal tract that facilitate the movement of food, liquids, and waste through the digestive system. This process is essential for proper digestion, nutrient absorption, and waste elimination.
Gut-Brain Axis: The gut-brain axis refers to the bidirectional communication between the gastrointestinal tract and the central nervous system. This complex network involves the interaction between the gut microbiome, the enteric nervous system, and the brain, allowing for the integration of signals that influence various physiological and behavioral processes.
Insoluble Fiber: Insoluble fiber is a type of dietary fiber that cannot be dissolved in water. It passes through the gastrointestinal tract largely intact, adding bulk to stool and promoting regular bowel movements. This fiber type is an essential component of a healthy diet, with implications across carbohydrate metabolism, gastrointestinal wellness, and overall nutritional strategies.
Intestinal Permeability: Intestinal permeability refers to the ability of the intestinal lining to selectively allow the passage of nutrients, water, and other molecules while restricting the entry of harmful substances, pathogens, and toxins. This term is crucial in understanding the nurse's role in promoting gut health, evaluating nutritional strategies to impact gastrointestinal wellness, and the impact of nutrition on gastrointestinal wellness across the lifespan and in chronic gastrointestinal illnesses.
Irritable Bowel Syndrome: Irritable bowel syndrome (IBS) is a chronic gastrointestinal disorder characterized by recurrent abdominal pain, discomfort, and altered bowel habits, such as diarrhea, constipation, or a combination of both. IBS is a complex condition that can significantly impact an individual's quality of life and is an important consideration in the promotion of gut health, the assessment and analysis of the impact of nutrition on the gastrointestinal system, the planning and evaluation of nutritional strategies to improve gastrointestinal wellness, and the impact of nutrition on gastrointestinal wellness across the lifespan.
Malabsorption: Malabsorption is a condition in which the body is unable to properly absorb and utilize essential nutrients from the food consumed. This can lead to deficiencies and a range of health issues across various bodily systems.
Microbiome: The microbiome refers to the diverse community of microorganisms, including bacteria, viruses, fungi, and protozoa, that reside within the human body, particularly in the gastrointestinal tract. These microorganisms play a crucial role in various aspects of human health and nutrition.
Parenteral Nutrition: Parenteral nutrition refers to the intravenous administration of nutrients, including carbohydrates, proteins, lipids, vitamins, and minerals, to individuals who are unable to meet their nutritional needs through oral or enteral (tube) feeding. This method of nutrition delivery bypasses the gastrointestinal tract, providing essential nutrients directly into the bloodstream to support various aspects of health, including hematologic, pulmonary, and gastrointestinal wellness.
Probiotics: Probiotics are live microorganisms, primarily bacteria, that when consumed in adequate amounts, provide health benefits to the host. They are often referred to as the 'good' or 'friendly' bacteria that reside in the human gastrointestinal tract and play a crucial role in maintaining gut health and overall well-being.
Short-Chain Fatty Acids: Short-chain fatty acids (SCFAs) are a group of saturated fatty acids with fewer than 6 carbon atoms. They are produced primarily through the fermentation of dietary fiber by gut bacteria and play a crucial role in promoting gut health and overall gastrointestinal wellness.
Small Intestine: The small intestine is a vital part of the human digestive system, responsible for the absorption of nutrients from the food we consume. It is a long, coiled tube that connects the stomach to the large intestine, playing a crucial role in the physical assessment of digestive organs, the function of digestive organs, the assessment and analysis of the impact of nutrition on the gastrointestinal system, the planning of nutritional strategies to impact gastrointestinal wellness, and the evaluation of nutritional strategies to impact gastrointestinal wellness.
Soluble Fiber: Soluble fiber is a type of dietary fiber that dissolves in water, forming a gel-like substance in the digestive tract. This fiber plays a crucial role in carbohydrate metabolism, gastrointestinal health, and the implementation of nutritional strategies to promote overall wellness.