BILD 2 LOs

Describe the three components of the cardiovascular system with their functions.

Blood, blood vessels, and the heart.

Predict how perturbations in levels of blood sugar, insulin, or glucagon, such as in diabetes, will affect the homeostatic control of blood glucose levels. 1. blood glucose levels rise. 2. blood glucose levels fall.

1. Blood glucose levels rise >> beta cells in pancreas secrete insulin >> liver takes up glucose and stores is as glycogen + body cells take up glucose >> blood glucose level declines >> back to normal blood glucose 2. Blood glucose levels fall >> alpha cells in pancreas secrete glucagon >>liver breaks down glycogen and releases glucose >> blood glucose level rises >> back to normal blood glucose

Predict how perturbations in levels of blood sugar, insulin, or glucagon, such as in diabetes, will affect the homeostatic control of blood glucose levels. 1. Blood glucose levels rise; what is the sensor, control center, and effector? 2. Blood glucose levels fall; what is the sensor, control center, and effector?

1. Blood glucose levels rise. • Sensor: beta cells of pancreas and glucose sensors of hypothalamus • Control center: beta cells of pancreas and hypothalamus. • Effector: liver and body cells. 2. Blood glucose levels fall. • Sensor: alpha cells of pancreas and glucose sensors of hypothalamus. • Control center: alpha cells of pancreas and hypothalamus. • Effector: liver.

Describe the digestion and absorption of the three major macronutrients in humans(carbohydrates, proteins, and fats), including the enzymes and other molecules, like bile, involved and the organs that secrete them.

1. INGESTION • eating; start of digestion process (occurs in oral cavity). 2. DIGESTION • The breakdown of food into smaller molecules (occurs in mouth → stomach → small intestine). 3. ABSORPTION • nutrient uptake into cells (SI → LI). 4. ELIMINATION • The removal of waste from the body (occurs in LI → anus). ACCESSORY ORGANS: supply enzymes and other substances for digestion. • salivary glands • gallbladder • liver • pancreas

Describe the mechanism of exchange of materials in capillaries

1. Very small blood vessels found throughout the body forexchange of nutrients, O2, and waste. Because they are so small, blood cells are forced to slow down; slow blood flow beneficial for nutrient exchange. 2. Short distance between capillaries and your cells so exchange is fast and efficient. 3. Pressure difference for nutrient exchange. • Capillary walls have openings through which small molecules like water, ions, and glucose can diffuse through, but NOT blood cells or large proteins like albumin.

2. Digestion (Stomach) Cont. Explain ways of protecting the stomach cells from the acidic condition

1. • Parietal cells: release H+ and Cl- separately to prevent cells from becoming too acidic. • Chief cells: release pepsinogen (inactive precursor) into lumen of stomach and HCl activates pepsinogen into pepsin (active enzyme). • Pepsin activates even more pepsinogen to pepsin (positive feedback). 2. Mucus released by mucous cells. 3. Secretion of pepsinogen and HCl is regulated (only secreted then needed). What if protection fails? • Gastric ulcers (mucus protection layer is reduced). • Heartburn/acid reflux (gastric acid pushed into the esophagus). Treatment • Inhibit H+ secretion from parietal cells (e.g. Nexium medication). • Neutralized pH of stomach via bicarbonate (e.g. TUMS).

Describe the mechanism of exchange of materials in capillaries

3. Pressure difference: force needed to push nutrients from capillaries to interstitial fluid • Blood pressure: the force that pushes nutrients out of capillaries → into the interstitial fluid for cells to take up • Osmotic pressure: the force that allows water, CO2, waste to travel from the interstitial fluid → back into capillaries. - Occurs from blood proteins like albumin attracting water back into capillaries (i.e water travels from low to high solute concentration). • Difference in BP & osmotic pressure determines net movement. 1. If BP > OP, net movement out of capillaries. 2. If BP = OP, no net movement 3. If BP < OP, net movement into capillaries (reabsorption of water into blood). • Blood pressure drops as it passes through capillaries, but osmotic pressure usually remains constant. - Arterial end: net movement is from capillaries into interstitial fluid. - Venous end: if osmotic pressure is higher, net movement is from interstitial fluid into capillaries.

Expand the form-function relationship for diverse living environments, changes in external and internal conditions, and disease states of organisms.

ANATOMY: the biological structure of an organism. PHYSIOLOGY: biological function. • The rate of exchange is proportional to the SA. • The amount of material that must be exchanged is proportional to the total body VOLUME. Advantages of multicellular life • Cells and organs can be specialized and work together (increased efficiency and fine-tuned functions). • Larger size which is good for defense. • Controlled shape to adapt to environment (e.g., birds are streamlined, humans walk on two feet). • Can live on land Disadvantages of multicellular life Absorbing nutrients/oxygen from the environment into all cells of an organism and removing waste.

Use the concept of a pressure gradient to explain blood flow.

Circulatory system uses a positive pressure gradient to move blood throughout the body; blood moves from area of high pressure → low pressure. • When our heart pumps blood, this will increase pressure and allow blood to move OUT via arteries → arterioles → capillaries for nutrient/O2 exchange → venule → come back to heart via veins

Components of a Homeostatic System

Components of a Homeostatic System: • Body achieves homeostasis by maintaining a variable at a set point/range • Sensor: recognizes the change in variable and signals the control center. • Control center: receives info and signals an effector. - usually hypothalamus is always one of the control centers. • Effector: organ or cells that generate a response to return to sent point/range

Type 1 vs Type 2 Diabetes

DIABETES: blood sugar levels that stay too high. Type 1 • Beta cells of pancreas are destroyed (NO sensor or control center) → cannot produce insulin → effectors aren't signaled to take up glucose. • autoimmune disease, usually genetic; treatment is insulin injection. Type 2 • Insulin receptors on effectors are internalized or reduced → effectors don't respond to insulin to take up glucose even when insulin levels are high • diet, obesity, stress, lack of physical activity; treatment is lifestyle changes. • Beta cells of pancreas are destroyed (NO sensor or control center) →

GI Tract

GASTROINTESTINAL TRACT 1. Mouth 2. Esophagus 3. Stomach 4. Small intestine 5. Large intestine ACCESSORY ORGANS (supply enzymes and other substances for digestion): • Tongue + salivary glands → Liver + gallbladder + pancreas MOUTH • Mechanical digestion - breaking down by teeth. • Chemical digestion - salivary glands secrete saliva that contains salivary amylase to digest carbohydrates. • Break up food → digest starch → moisten food to create bolus PHARNYX (THROAT): a common passageway for food and air intake: • Advantage - speak and sing • Disadvantage - choke

Use the concept of partial pressure to predict gas exchange directions of O2 and CO2 in and out of the blood.

Gas exchange in the body: direction is determined by O2 partial pressure and CO2 partial pressure. • PO2 entering alveolar space similar to atmosphere and is much higher than PO2 in alveolar capillaries (because this is O2 poor blood). • PCO2, ↑ at tissues & ↓ in alveolar spaces • PO2, ↑ in alveolar spaces & ↓ at tissues. Inhale O2 into alveolar spaces → O2 diffuses into alveolar capillaries(O2 moves from high PO2 to low PO2) → pulmonary veins & systemic arteries → systemic capillaries (PO2 high in blood and low in body tissue so O2 diffuses from capillaries to body tissue; PCO2 high at body tissue and low in capillaries so it diffuses into bloodstream) → systemic veins & pulmonary arteries → blood enters alveolar capillaries where CO2 is exhaled out of alveolar spaces (CO2 moves from high PCO2 to low PCO2)

Understand dissociation curves for hemoglobin and find oxygen saturation of hemoglobin under a given condition.

How does intense exercise affect pH levels near tissues? • lower pH → curve shifts to right. - In very active tissues like when exercising, body generates ↑ CO2, ↑ H+, ↓ O2 affinity, ↑ availability for tissues ↑ acidity (low pH). - At the same PO2, hemoglobin releases more O2 to be available for muscle cells when pH=7.2. • Higher pH: ↓ CO2, ↓ H+, ↑ O2 affinity, ↓ availability for tissues.

Describe the digestion and absorption of the three major macronutrients in humans(carbohydrates, proteins, and fats), including the enzymes and other molecules, like bile, involved and the organs that secrete them.

MACRONUTRIENTS: nutrients that the body needs in large amounts. • Carbs → broken down into sugars. • Proteins → broken down into amino acids. • Fats/lipids → broken down into fatty acids and glycerol. Body needs to absorb nutrients for cellular and bodily functions, and to make ATP/energy

Describe feedback loops

NO FEEDBACK LOOP: Change in variable X causes effects on Y and Z, etc. Z does not affect X. • Change in X → Change in Y → Change in Z FEEDBACK LOOP: Change in X causes effects on Y and Z, etc., which then affects X again. • Increase in Z affects the upstream of that biological system.

Use the concept of partial pressure to predict gas exchange directions of O2 and CO2 in and out of the blood.

Need to consider the partial pressure of gases in atmosphere compared to the partial pressure of gases in our lungs. • Partial pressure = pressure exerted by a particular gas in a mixture of gasses. • A gas diffuses from a region of higher partial pressure → a region of lower partial pressure. • Our cells are always using O2 so the PO2 at body cells is ↓ • O2 is used by body cells in cellular respiration, waste product is CO2; body cells have ↑PCO2

Understand the forms of multicellular organisms and their functions at the levels of organ systems, organs, tissues, and cells.

Organism → Organ systems → Organs → Tissues → Cells 1. TISSUES: group of cells with a similar appearance and a common function. a) Epithelia • Cover the outside of the body and line organs and cavities within the body. • They function as a barrier against mechanical injury, pathogens, and fluid loss because they are closely packed often with tight junctions. • Form active interfaces with the environment. b) Connective Tissue • Consisting of a sparse population of cells scattered through an extracellular matrix, holds many tissues and organs together and in place. • Within the matrix are numerous cells called fibroblasts, which secrete fiber proteins, and macrophages, which engulf foreign particles and any cell debris by phagocytosis. c) Muscle Tissue • The tissue responsible for nearly all types of body movement. • Three types of muscle tissue in the vertebrate body: skeletal, smooth, and cardiac. 2. ORGANS: functional units where different types of tissues are further organized into. 3. ORGAN SYSTEM: made up of a group of organs that work together, providing an additional level of organization and coordination.

Distinguish the functions of the pulmonary circuit and the systemic circuit

PULMONARY CIRCUIT: moves blood between the heart and lungs; transports deoxygenated blood to the lungs to absorb O2 and release CO2. 1. Right ventricle pumps O2-poor blood to lungs via pulmonary arteries. 2. Blood loads O2 and unloads CO2. 3. O2-rich blood returns via pulmonary veins to left atrium. SYSTEM CIRCUIT: moves blood between the heart and the rest of the body; carries oxygenated blood away from the body, and returns deoxygenated blood back to heart. 4. O2-rich blood flows from left atrium into left ventricle, which pumps blood out of the aorta (largest systemic artery; sends blood to all different parts of your body except your lungs) 5. O2 is supplied to body cells and CO2 is loaded into blood through capillaries. 6. O2-poor blood returns through vena cava (largest systemic vein) and into the right atrium.

Apply knowledge to assess and solve novel problems in a scientific way.

SA:V • SA/V ratio tells us how efficient the rate of nutrient exchange is between a cell and its environment >> we can compare of the rate of nutrient exchange between different organisms. • We want SA/V ratio to be as large as possible for fast exchange between a cell and its environment. • The problem with large, multicellular organisms is that there is a disproportionate increase in the SA as the volume gets larger. >> As a cell gets bigger, the volume gets large much more quickly than the SA. Two examples of how large organisms can maintain a high SA/V Ratio • Having multiple smaller cells instead of one large cell allows us to have higher rate of nutrient exchange. • Specialized surfaces for efficient exchange: epithelial cells facing the lime of the small intestine have microvilli (long, thin projections).

Describe an example of homeostasis and feedback controls in biological systems: e.g. Body temperature increases; what is the sensor, control center, and effector(s)?

Sensor: thermo-sensors in skin and hypothalamus. Control Center: hypothalamus Effector: sweat glands and blood vessels.

3. Absorption (SI & LI) Describe the structure of the small intestine that increases the surface area for efficient absorption

Small Intestine • Absorption of amino acids and sugars now possible. • Sugars and amino acids absorbed by cells of SI → loaded into bloodstream → moves to liver to remove any toxins → finally moves to rest of body. Large Intestine • Functions in water and ion absorption • Approximately 2L water per day goes through the LIs and it is able to reabsorb so much water that you only excrete about .2-.5L of water by the end of the process. 4. Elimination

Explain how lungs and respiratory system organs move during breathing using the terms of volume and pressure.

Structure of the Respiratory System: • Breathing in through nasal and oral cavity → larynx (open when you are breathing; larynx closes and esophagus opens when you are eating) → trachea → bronchi → bronchioles → alveoli. - Alveoli: small air sacs with large SA, surrounded by logs of capillaries for O2 exchange.

Explain how lungs and respiratory system organs move during breathing using the terms of volume and pressure.

Ventilation (neg pressure breathing): • P and V, inversely related (↑V, ↓P) • Air flows from ↑P to ↓P • Assume atm isn't changing. 1. INHALATION: diaphragm contracts (moves down)/rib cage expands as rib muscles contract → ↑V lung (↓P lung) → this pulls in air from the atmosphere to the lungs. 2. EXHALATION: the diaphragm relaxes (moves up)/rib cage gets smaller as rib muscles relax → ↓V lung (↑P lung) → breathing out.

Purpose of the circulatory system

allows for very short diffusion of nutrients into blood vessels, which carry nutrients to body cells. • Only a little diffusion needed for nutrients to move from blood vessels to body cells (↓ distance of exchange, ↑ rate of diffusion) • Transport of nutrients, O2, waste, CO2, hormones, immune cells.

Understand what forces generate blood pressure. Distinguish between systolic anddiastolic blood pressure

• Blood pressure: pressure that blood exerts against the walls of a vessel. •Blood pressure changes regularly during ventricular systole and ventricular diastole (higher bp during ventricular systole and lower bp during ventricular diastole). - BP: 120/80 mmHg (120 is ventricular systolic pressure & 80 is ventricular diastolic pressure). • As blood travels further from the heart, blood pressure will decrease. - Along the blood vessels, resistance and less pressure pushing blood forward. - Therefore, arteries have higher bp but veins have lower bp.

2. Digestion (Mouth)

• Breaks down food mechanically (chewing) and chemically (saliva). • Carbohydrate digestion starts in mouth chemically. - AMYLASE in saliva breaks down polysaccharides → into maltose & smaller polysaccharides. • BOLUS: food after processing and saliva breakdown; moves through esophagus.

2. Digestion (Stomach)

• Good for temporary storage, mixing, and chemical digestion of bolus. • Protein digestion starts in stomach. • Two components of gastric juice that are secreted into stomach lumen: HCl (acid) + pepsin (protease = enzyme that breaks down protein into smaller polypeptides). • Three functions of HCl: 1. Antibacterial function to kill harmful bacteria. 2. Denaturation/unfolding of proteins. 3. Activates pepsin

Understand dissociation curves for hemoglobin and find oxygen saturation of hemoglobin under a given condition.

• In pulmonary capillaries we breathe in O2 so PO2 is 100 mm Hg, and O2 saturation of hemoglobin is 100% - HG-4O2 (fully bound) • In tissues at rest PO2 is 40 mm Hg, and O2 saturation decreases to about 70% - HG-3O2 + 1 free O2 to diffuse to body cells • As PO2 decreases, hemoglobin has less affinity for O2 and more is available to tissues.

2. Digestion (SI)

• Most digestion and absorption of carbs, proteins, and fats occurs in small intestine. • Digestion for all three ENDS in SI. • Digestion requires help from accessory organs. - Most carbs and proteins are digested by enzymes secreted from pancreas and SI. - Fat digestion needs help of bile salts, which are made by liver and stored in gallbladder. • Bile salts physically emulsify fat globules in SI, increasing exposure of triglycerides to hydrolysis. • Pancreatic lipase chemically breaks down triglycerides into fatty acids and glycerol.

Describe the forms in which O2 and CO2 are transported in blood.

• O2 transport in blood occurs via hemoglobin (found in red blood cells). - Hemoglobin made of 4 globin proteins; 4 iron/heme centers that each bind 1 O2 - ↑ PO2 = ↑ O2 saturation/affinity for hemoglobin. - ↓ PO2 = ↓ O2 saturation/affinity for hemoglobin. • CO2 transport: - Majority of CO2 produced by cells is dissolved in blood as bicarbonate. - More CO2 → more H+ → lower pH (more acidic) - Less CO2 → less H+ → higher pH (more basic).

Negative Feedback Loop

• Occur when a change in the level of something causes an effect that counteracts that change. • Good for stability. e.g. body temperature, blood glucose levels, blood CO2

Positive Feedback Loop

• Occurs when a change in the level of something causes an effect that amplifies that change. • Downstream reinforces the upstream.

Explain the cardiac cycle using the terms of diastole, systole and heart sounds

• SYSTOLE: contraction phase (high pressure) • DIASTOLE: relaxation phase (low pressure) • Atrioventricular valves (AV): valves between the atrium and ventricle; prevents back flow of blood from ventricle to atrium. • Semilunar valves (SL): valves between the ventricle and artery; prevents back flow of blood from artery to ventricles. CARDIAC CYCLE (high → low pressure) 1. Atrial and ventricular diastole: all 4 chambers of heart in relaxed state (passive filling of blood into atria and ventricles; AV open and SL closed (dub)) 2. Atrial systole occurs while ventricular diastole occurs to pump blood from atria to ventricles (AV open and SL closed) 3. Ventricular systole and atrial diastole occurs to pump blood from ventricles to arteries (AV closed (lub) and SL open (dub) bc ventricular pressure high and arterial pressure low).