UNIT 12ANIMAL ANATOMY AND

PHYSIOLOGYIntroduction, Digestive, Circulatory,

and Respiratory Systems(Chapters 40, 41, and 42)

EpithelialTissue

Simple = single layer

Stratified = multiple layers

Connective Tissue

Tightlypacked

Sparse in extracellular matrix

Collagen Fibers=Nonelastic/tensil strength

Elastic Fibers =Elastin

Reticular Fiber =Joins to Tissues

Tendons = Muscle BoneLigaments = Bone BoneHolds organs

In place

OsteoblastsCa, Mg, P

Nervous Tissue

Muscle TissueLong “Contracting” Cells/ Fibers

Voluntary Movements

Heart Contraction

Involuntary ActivitiesWalls of Digestive Tract, Bladder, Arteries, etc.

InterstitialFluid

Negative Feedback =The change in the variable being monitored triggers the control mechanism to counteract further change in the same direction

1. Receptor (detects change)

2. Control Center (processes information)

3. Effector (response)

Biofeedback Circuits

Positive Feedback =A change in a variable that triggersmechanisms that amplify the change

Child BirthContractions

Pressure of baby’s head on Uterus Contractions + Pressure More Contractions

Bioenergetics of an Animal

Metabolic Rate = the sum of all the energy-requiring biochemical reactions occurring over a given time interval

Energy measured in:calories (c)kilocalories (kcal or C)

Inverse relationship with size:Smaller = Higher Metabolic Rate

Higher breathing rate and heart rateEat more food per unit body mass

“The amount of energy an animal uses per unit time”

Surface Area to Volume = Maintaining Temp

Basal Metabolic Rate (BMR) = Endotherm at Rest, Fasting, No StressStandard Metabolic Rate (SMR) = Ectotherm at Rest, Fasting, No Stress

Male Human BMR = 1,600-1,800 kcal/dayFemale Human BMR = 1,300-1,500 kcal/day

Maximum Metabolic Rates

Total Annual Energy Expenditures

Energy Expenditures per Unit Mass

CHAPTER 41: ANIMAL NUTRITION

Homeostatic Regulation

Glucose energy surplus stored as Glycogen in Liver and Muscle CellsLiver glycogen expended first, then fat glycogen, then muscle glycogen

Blood Glucose is High

Pancreas secretes Insulin

Insulin enhances the transport of glucoseinto body cells and stimulates the liver and muscle cells to store glucose as glycogen= blood glucose level drops

Blood Glucose is Low

Pancreas secretes Glucagon

Glucagon promotes the breakdown of glycogen and the release of glucose into the blood = blood glucose level rises

Essential Amino Acids

“Essential Nutrients”

Essential Fatty Acids(Synthesize Most that are Needed)

Vitamins =organic molecules needed in small quantities

Minerals =simple inorganic molecules needed in small quantities

Heterotrophic-Herbivores-Carnivores-Omnivores

Ingestion Adaptations-Suspension Feeders-Substrate Feeders-Fluid Feeders-Bulk Feeders

Caterpillar

Feces

4 Stages of Food Processing-Ingestion-Digestion Enzymatic Hydrolysis-Absorption-Elimination

Specialized Compartmentsfor Digestion

(Don’t Digest Yourself)

Sponges and Heterotrophic Protist= Food Vacuole

“Intracellular”

“Extracellular”

Hydra (Cnidarian)Gastrovascular Cavity

Complete Digestive Tract“Alimentary Canal”Specialized Compartments

Directional Flow

The Mammalian Digestive System

Peristalsis

Salivary Amylase =Hydrolyzes Starch and Glycogen

Physical and Chemical Digestion

Dentition

Saliva =+ 1 Liter/day of SalivaMucin – Glycoprotein protects cells and lubricatesBuffers – Neutralize food for tooth decayAntibacterial AgentsSalivary Amylase

Swallow Reflex

Bolus Windpipe moves upwardGlottis and Epiglottis“Went down wrong pipe”

Voluntary

Involuntary

StomachUpper Abdominal CavityElastic/Accordianlike FoldsStore 2 Liters of food

Chemical Digestion:Gastric Juice-Secreted from the Epithelium Lining-HCl (pH 2) Secreted by the Parietal cells Disrupt Extracellular Matrix that binds cells together Kills most bacteria from food Denatures (unfolds) proteins-Pepsin – begins hydrolysis of proteins (peptide bonds) Pepsinogen- Inactive form secreted from Chief cells Activated by the HCl in the lumen of the stomach (+ feedback)

Mucus:-Secreted by the Epithelium cells-Protect stomach lining -Mitosis replaces stomach lining every 3 days

Mechanical Digestion:-“Churning” from smooth muscle tissue-Hunger Pangs when stomach is empty-Acid Chyme – contents of the food in the stomach

Cardiac Sphincter – “Heartburn”Pyloric Sphincter – 2-6 hours for stomach to empty

Small Intestine~6 meters in humanMost of the enzymatic hydrolysisMost of the nutrient absorption

Duodenum-First 25 cm-Chyme mixes with digestive juices from the pancreas, liver, gallbladder and gland cells from the intestinal wall

Bile Salts-Digestion of Fats-Pigments “Brown”

Hydrolytic EnzymesAlkaline Solution (Bicarbonate) Buffer acidity of Chyme

MaltaseSucraseLactase

Pancreatic Enzymes-Inactive Form-Enteropeptidase Activates Trypsin-Trypsin Activates the others

Emulsification – keep fats from coalescing

Rest of the Small Intestine-Jejunum-ileum

Most of the Nutrient Absorption-A few nutrients in stomach and large intestine

Large Surface Area~300m2 (size of a tennis court)-Villi = fingerlike projections in lining-Microvilli = microscopic extensions of the villi

Absorption across epithelial cells blood vesselsBlood Vessels (Capillaries)Lacteal – small vessel of the lymphatic systemPassive Diffusion – some simple sugars like fructoseActive Transport – amino acids, small peptides, vitamins, glucose

Animals expend 3-30% of the chemical energy contained in food during digestion and absorption

The Large Intestine: “Colon”-1.5 meters long-U-shaped-Water Absoption (90% efficient)

Cecum- Appendix (Lymphoid Tissue)

Feces-Peristalsis-12-24 hours for feces to travel its length-Diarrhea = Irritation of the lining and less water absobed-Constipation = Feces moved too slowly (+ water absorption)-Fiber = helps move along

Microorganisms-E.coli as an example-Gases: Methane and Hydrogen Sulfide-Produce Vitamins: Biotin, Folic Acid, K, B-Indicators of contaminated water supply

Rectum-Stores Feces-Sphincters: Involuntary and Voluntary- “Bowel Movement”

Hormones Regulate Digestion

Gastrin-Stimulated by food-Secretion of Gastric Juice

Enterogastrones-Secretin From Duodenum lining Secretion of Bicarbonate (Pancreas)-Cholecystokinin (CCK) Gall Bladder to release bile into Duodenum

Structural Adaptations

Dentition

Fermentationchamber

Microorganisms (Ruminant)

Length of Intestines

Bacteria and Protists

cud

Water Removal

Chapter 42: Circulation and Gas Exchange

Gastrovascular Cavities for Transport

Diffusion

Open Circulatory System

Thin Tissue

Common Features:1. Circulatory Fluid2. A Set of Tubes3. A Muscular Pump4. Fluid Pressure

Hemolymph – blood andinterstitial fluid mix

Sinuses – spaces surrounding the organs Vessels branch into smaller vessels

Blood – not mixed with interstitial fluid

Closed Circulatory System

Insects, other Arthropods, and most Mollusk Earthworms, Squid,

Octopus, Vertebrates

Circulatory System

Cardiovascular System (Vertebrates)

Two Chambered Heart:-Gill Circulation = Blood/Respiratory-Systemic Circulation = Blood/Body-Two capillary beds lowers pressure

Heart Chambers:-Atria = Receiving Chambers-Ventricles = Pumping Chambers

Vessels:-Arteries = Carry Oxygenated Blood-Veins = Carry Deoxygenated Blood-Capillaries = Infiltrate Tissue/Diffusion

Pathway of Blood:Heart Arteries Arterioles Capillaries TissueTissue Capillaries Venules Veins Heart

High Metabolic Rate = More Complex Circulatory System and More Powerful Hearts

Three Chambered Heart:-Pulmocutaneous Circuit= lungs/skin-Systemic Circuit= body-Double Circulation= pumped twice/ Maintains pressure-Ventricle= some mixing of blood but a ridge diverts most of the blood into the correct circuit

Four Chambered Heart:-No Mixing of Blood-Pulmonary Circuit = lugs-Systemic Circuit = body-Double Circulation-Allowed Endothermic (use 10% more energy)

Pulmonary Circuit (Lungs)

Systemic Circuit (Body)

Mammalian Double Circulation

Systemic Circuit (Body)

Arteries = Oxygen RichVeins = Oxygen Poor

Mammalian Heart-Below sternum-Size of a fist-Mostly cardiac tissue

(AV)

-Chambers-Vessels-Valves

Atria:-Thin walls-Collection chambers for returning blood-Pump only to the ventricles

Ventricles:-Thick walls-Pumping chambers-Right Ventricle Lungs-Left Ventricle Body

The Cardiac Cycle-One complete sequence of pumping and filling (rhythmic)-Contracts = Pumps-Relaxes = Chambers fill

Systole = Contraction phaseDiastole = Relaxation phase

Cardiac Output = volume of blood per minute from the left ventricle Dependent upon: Heart Rate (number of beats per minute) Stroke Volume (amount of blood pumped by left ventricle) Avg ~75mL If stroke volume is 75mL and heart rate 70bpm then Cardiac Output = 5.25 L/min Equivalent to the total volume of blood in the body Increases during exercise

Valves (4):-Connective tissue-Prevent backflow-Atrioventricular (AV) valves – between atria and ventricle Close during ventricular contraction-Semilunar valves – anterior ends of the ventricles Open during ventricular contraction Close following contraction

Pulse = rhythmic stretching of arteries caused by the pressure of blood driven by ventricle contractionMeasure heart rate by measuring your pulse

Heart Sounds:-Closing of the valves-“Lub-dup”-Lub –created by the recoil of blood against the closed AV valves-Dup –recoil of blood against the semilunar valves

Heart Murmur:-Defect of one of the valves-Hissing sound when a stream of blood squirts backwards through a valve-Born with or damaged by infection (rheumatic fever)-Usually do not reduce the efficiency of blood enough to warrant surgery

Maintaining the Rhythmic Beat of the Heart-Brain cells within a few minutes without oxygen-Maintaining the beat is critical for survival

Sinoatrial (SA) Node:-Self excitable (contract w/o nervous system)-”Pacemaker” -Sets the rate and timing in which all cardiac muscles contract-Anterior wall of right atrium-Produces electrical impulses-Contract atria in unison (both at the same time)

Atrioventricular (AV) Node:-Between wall of right atrium and right ventricle-Impulses delayed ~0.1 second (ensures atria are completely empty)-Impulse relayed to ventricles in unison via the bundle branches

Electrocardiogram (ECC or EKG):-Use electrodes to record the heart cycle-Measures heart impulses that are conducted through body fluids to the skin

Bundle Branches and Purkinje Fibers (muscle fibers):-Conduct the signal from the AV node to the apex of the heart-Ventricles contract from the apex toward the atria

re-priming of ventricles

Atria Systole Ventricle Systole

Physiological Cues Influence SA node:-2 sets of nerves (1 speeds up the pacemaker and 1 slows it down)-Hormones: Epinephrine “fight or flight” from adrenal gland speeds it up-Body Temperature: increase in 1oC raises heart rate by ~10 beats/min (fever=+rate)-Exercise

Vessel Structure

Similarities between Arteries and Veins:-Connective tissue with elastic fibers (exterior)-Smooth muscle tissue with elastic fibers-Endothelium – single layer of flattened cells; minimizes flow resistance

Differences between Arteries and Veins:-Arteries Thicker middle and outer layers = higher velocity and pressure Highly elastic Blood moves due to pressure-Veins Thinner walls = lower velocity and pressure Blood moves due to skeletal muscles pinching the veins and smooth muscle tissue contractions (peristalsis) Valves that allow unidirectional flow to heart

Capillaries:-Lack the outer two layers-Very thin walls with basement membrane-Facilitates the exchange of substances between the blood and interstitial fluid

Artery

Vein

Blood Flow Velocity

Blood travels over a thousand times faster in the aorta (~30 cm/sec) than in capillaries (~0.026 cm/sec)

Vessel Area increases due to the increase in the total number of vessels = Total Area

Velocity decreases as the vessel area increases

Blood Pressure= the hydrostatic force that blood exerts against the wallof a vessel and that propels blood

Fluids exert a force called hydrostatic pressure against surfaces they contactFluids flow from areas of high pressure to low pressure

Peaks in blood pressure corresponding to ventricular systole alternate with lower blood pressures corresponding to diastole

Resistance to flow through the arterioles and capillaries, due to contact of the blood with a greater surface area of endothelium, reduces blood pressure and eliminates pressure peaks

Healthy 20 year old = 120 mm Hg/ 70 mm Hg

Sphygmomanometer cuff inflated to+120 mm Hg (pressure of cuff exceeds pressure of artery)

-Stethoscope s used to listen for sounds of blood flow-Cuff is gradually deflated until blood pressure exceeds cuff pressure (hear blood pulsing) = Systolic Pressure

Cuff is further loosened until the blood flows freely (no sound) = Diastolic Pressure

Capillary Exchange

Lymphatic System:-Returns blood fluids and blood proteins back to the blood-Fluid enters by diffusing into tiny lymph capillaries intermingled among capillaries of the cardiovascular system-Lymph – the fluid in the lymph capillaries-Drains into the circulatory system near the junction of the venae cavae with the right atrium-Lymph vessels have veins to prevent backflow-Depend on skeletal/smooth muscle contractions for movement-Lymph nodes = connective tissue filled with white blood cells specialized for defense (filter pathogens)

-So much blood passes through the capillaries that the cumulative loss of fluid adds up to about 4 L per day-There is also some leakage of blood proteins

Lymphatic System

Blood-Connective Tissue-Specialized cells suspended in a liquid matrix (plasma)

90%Ions:-Inorganic salts in the form of ions -“blood electrolytes”-Maintain osmotic balance-Help buffer = pH 7.4-Muscle and nerves depend upon-Kidney helps maintain electrolytes

Plasma Proteins:-Buffers against pH changes-Maintain osmotic balance-Contribute to viscosity (thickness)-Some are escorts for lipids-Immunoglobulins = fight pathogens-Fibrinogens = clotting factors

Erythrocyte (Red Blood Cells):-Most numerous – 25 trillion in body’s 5L of blood-Structure = Function Small 7-8.5 micrometers in diameter Biconcave disks –thinner in the center Greater surface area for carrying/diffusing oxygen Mammalian cells lack nuclei = more space for hemoglobin Lack mitochondria = use anaerobic metabolism (+ efficiency) Hemoglobin – the iron containing protein for oxygen transport ~250 million molecules per cell Each hemoglobin can bind 4 oxygen molecules One erythrocyte can transport ~1 billion oxygen molecules

Leukocytes (White Blood Cells):-5 types (see diagram)-Collective function = fight infections-Monocytes and Neutrophils are phagocytes (engulf and digest bacteria and debris)-Spend most of their time outside of circulatory system patrolling in the interstitial fluid-Numbers increase temporarily when body is fighting an infection

Platelets:-Fragments of cells about 2-3 microns in diameter-No nuclei-Originate as pinched-off cytoplasmic fragments of large cell in the bone marrow-Function in blood clotting

Replacement of Cellular Elements in Blood-Cellular elements of blood wear out and are replaced constantly-Erythrocytes usually circulate for only ~3-4 months and then are destroyed by phagocytic cells in the liver and spleen Components are recycled into new erythrocyte cells through biosynthetic processes-These cellular elements develop from pluripotent stem cells in the red marrow of bones, particularly the ribs, vertebrae, breastbone, and pelvis-Pluripotent = have the ability to differentiate into any type of blood cell or into cells that produce platelets

Leukemia:-A cancerous line of the stem cells that produce leukocytes-The cancerous stem cells crowd out cells that make red blood cells and produce an unusually high number of leukocytes, many of which are abnormal-Treatment is to remove pluripotent stem cells from a patient, destroy the bone marrow, and restock it with noncancerous pluripotent cells-As few as 30 of these cells can repopulate the bone marrow

Blood Clotting-Fibrinogen = sealant (inactive form)-Fibrin (active form) aggregates into threads Clot-Clotting factors, derived from platelets, begin the process-Clotting factors activate fibrin from fibrinogen

Hemophilia:-Inherited defect in any step of the clotting process-Treated by injections correcting the defected step

Thrombus:-Spontaneous clot that develops when platelets clump and fibrin coagulates within a vessel-Normally, anticlotting factors in blood prevent spontaneous clotting-Potentially dangerous (cardiovascular disease)-”Throw a clot” Stroke if brain oriented or Heart Attack if heart oriented

Cardiovascular Disease-Diseases of the heart and blood vessels-Cause more than half the deaths in the US

Stroke:= the death of nervous tissue in the brain, usually resulting from rupture or blockage of arteries in the head

Both frequently result from a thrombus that dislodges and clogs an artery

Atherosclerosis:= build up of plaque on the inner walls of the arteries, narrowing their bore-Can be caused by cholesterol-Encourage the development of thrombus formation

Arteriosclerosis:= the plaque becomes hardened by calcium deposits (“hardening of the arteries”)

Hypertension (high blood pressure):-Encouraged by atherosclerosis (narrowing vessels and reducing elasticity)-Can be controlled by diet, exercise, medication, or a combination of these-Diastolic pressure greater than 90 = concern-200/120 = courting disaster

-These conditions can be inherited-Nongenetic factors such as smoking, lack of exercise, diet rich in animal fat, high cholesterol

Cholesterol:-Low-density lipoproteins (LDL’s) = “bad” cholesterol-High-density lipoproteins (HDL’s) = “good” cholesterol by reducing deposition-Exercise increases HDL’s-Smoking increases LDL’s

Normal Artery Artery partially closed by plaque

Heart Attack:= the death of cardiac muscle tissue resulting from prolonged blockage of one or More coronary arteries (the vessels supplying the heart muscle with oxygen/nutrients)

Gas Exchange in Animals: The Respiratory System

Role of Gas Exchange in Bioenergetics

-O2 in and CO2 out-Respiratory medium: atmosphere (terrestrial) and water (aquatic) Dissolved oxygen in water is always less than atmospheric oxygen-Respiratory surface = where gases are exchanged with environment Tend to be thin and have large surface areas Moist for diffusion Endotherms have a larger respiratory surface area than similar sized ectotherms Simple animals (sponges, cnidarians, flatworms) every cell is close enough to the external environment for diffusion = usually small, thin, flat, large surface area In more complex animals, the bulk of the body doesn’t have direct external access = respiratory organs

Diversity of Gill Structures

Gills = outfoldngs of the body surface that are suspended in the waterTotal surface area often exceeds that of the rest of the body

Distributed over most of the body Flip-like covering one segment

Restricted to a local body region

Structure and Function of the Gill-Oxygen concentration is very low in water-Gills must be very effective

Ventilation:-Increases the flow of medium over the gill-Crayfish/Lobsters have paddlelike appendages that drive the current-Fish Mouth Pharynx Gill Exits = pulled by operculum

Countercurrent Exchange:-Blood flows in opposite direction to the movement of water past the gill-Allows efficient transfer of oxygen to blood-As blood moves through a gill capillary, it becomes more and more loaded with oxygen, but it simultaneously encounters water with ever higher oxygen concentrations-Diffusion gradient favors the transfer of oxygen from the water to blood-Efficiency = 80% of dissolved oxygen is removed

Gills are unsuitable for terrestrial life:-Too much evaporation from moistened surface-Gills would collapse and cling together-Terrestrial animals have respiratory surfaces within the body with tubes opening to the atmosphere

Tracheal System (Insects)

Terrestrial AdaptationsAtmospheric AirAdvantages:-Higher concentration = ~210 mL/L compared to ~6 mL/L in water-Oxygen and carbon dioxide diffuse much faster = less ventilation required-Less energy needed to ventilate due to air being lighter and easier to pumpDisadvantages:-Desiccation of the large and moist respiratory structures – moved internally

-Made up of air tubes (tracheae), opened to the outside, that branch throughout the body-Gas exchange is through diffusion-Virtually every cell is within a short distance of the respiratory medium-The open circulatory system is not involved in transporting gases

Insect Flight:-Demands of gas exchange are heightened (10-200 times)-Alternating contractions/relaxation of flight muscles pump air through tracheae (ventilation)-Flight muscles are packed with mitochondria (bioenergetics)

Lungs-Lungs are restricted to one location-Circulatory system is needed to transport gases-Size and complexity is correlated with the animal’s metabolic rate

-Amphibians have relatively small lungs -Rely on diffusion through skin to supplement

-Reptiles, Birds, and Mammals rely entirely on lungs

Mammalian Respiratory SystemsLungs:-Located in the Thoracic (chest) cavity-Spongy texture-Honeycombed with a moist epithelium (respiratory surface)

Air Passage:Nostrils Nasal Cavity Pharynx Larynx Trachea Bronchi Bronchioles Alveoli ExchangeReversed for carbon dioxide

Nostrils/ Nasal Cavity– filtered by hairs, warmed, humidified, and sampled for odors

Larynx:-Cartilage-Voicebox with vocal cords-High pitch = cords are stretched tight and vibrate rapidly-Low pitch = less tightly and vibrate slowly

Trachea:-Cartilage-”Windpipe”

Epithelium Lining:-Covered by cilia and a thin film of mucus-Mucus traps contaminants (dust, pollen, etc)-Cilia beat and move the mucus upward to the pharynx where it is swallowed

Alveoli (Alveolus = singular):-Site of gas exchange-Millions in humans-Total surface area of 100 m2

-Oxygen dissolves and rapidly diffuses into capillaries-Carbon dioxide is reversed

Alveoli (SEM)

Negative Pressure BreathingBreathing = the alternate inhalation and exhalation of air that ventilates the lungs

Negative Pressure Breathing :-Works like a suction pump, pulling air instead of pushing it into the lungs

Inhalation:-Lung volume increases as a result of contraction of the rib cage muscles and the diaphragm-Contraction of the rib muscles expands the rib cage by pulling the ribs upward and the breastbone outward-At the same time, the chest cavity expands as the diaphragm contracts and descends like a piston-All these changes increase the lung volume, and as a result, air pressure within the alveoli becomes lower than atmospheric pressure-Because air flows from a region of higher pressure to lower pressure, air rushes through the respiratory tract to the alveoli

Exhalation:-Rib muscles and diaphragm relax-Lung volume is reduced-The increase of air pressure within the alveoli forces air up the tract

Vigorous Exercise:-Other muscles of the neck, back, and chest further increase ventilation volume-Raise the rib cage even more

Tidal Volume:-The volume of air an animal inhales and exhales with each breath-Average ~500 mL at rest in humans

Vital Capacity:-The maximum tidal volume during forced breathing-Approx 3.4 L and 4.8 L for college age male and females respectively

Residual Volume:-The air remaining in the lungs after we forcefully exhale as much as we can-Due to the lungs ability to hold more air than the vital capacity-Mixing of oxygen-rich and oxygen depleted air = decrease efficiency

Ventilation in Birds-Much more complex than in mammals-Birds have eight or nine air sacs that penetrate the abdomen, neck, and even the wings-These air sacs act as bellows that keep air flowing through the lungs

-Air flows through the interconnected system in a circuit that passes through the lungs in one direction only, regardless of inhalation or exhalation-Parabronchi = tiny channels through which air flows in one direction (not dead ends like alveoli)-This system completely exchanges the air in the lungs with every breath (maximizing lung oxygen concentrations)-Allows them to perform better at high altitudes (+9,000 meters during migration)

Breathing Control-We can hold our breath for a short period of time -We can consciously breath faster and deeper-Most of the time automatic mechanism regulate our breathing-This ensures coordination with the cardiovascular system

Breathing Control CentersMedulla Oblongata:-Sets the rhythm-Inhibited during conscious breathing-Monitors CO2 levels Monitors cerebrospinal fluid pH drops due to carbonic acid Increases depth and rate of breathing

Aorta and Carotid Arteries:-Monitor CO2 levels and relay to Medulla-Monitor O2 levels and relay to Medulla (high altitudes)

Coordination with circulatory system-During exercise, increase cardiac output is matched to the increased breathing rate, which enhances O2 uptake and CO2 removal as blood flows through the lungs

Oxygen Transport:-Hemoglobin (quaternary protein)-4 subunits each with a “heme” group-Each heme group has an iron molecule at its center-The iron binds oxygen-Each hemoglobin can carry 4 oxygen molecules-Hemoglobin binds oxygen reversibly (load and unload)-The binding of oxygen to one subunit induces shape change in other subunits-This change increases oxygen affinity-This process is reversed at the tissue due to the low concentration of oxygen in the tissue (gradient) and the pH of carbonic acid causing a confirmation change in the subunits

Carbon Dioxide Transport:-7% of CO2 released by respiring cells travels in plasma-23% binds to the amino groups of hemoglobin-70% is transported in the blood in the form of bicarbonate ions

-CO2 diffuses into plasma and then into rbc’s-Inside the rbc’s it is converted into bicarbonate-Carbon dioxide first reacts with water (assisted by carbonic anhydrase) to form carbonic acid-The carbonic acid then dissociates into a hydrogen ion and a bicarbonate ion-Most of the hydrogen ions attach to hemoglobin and therefore do not change the pH-The bicarbonate ions diffuse into the plasma-The process is reversed at the other end

Adaptations to Deep-Diving

-Humans can hold breath 2-3 minutes and swim to depths of 20 m or so-Weddell seal can swim to 200-300 m and hold breath for ~20 minutes (sometimes for more than an hour)-Penguins can do about the same-Elephant seals can reach depths of 1,500 m (almost a mile) and stay submerged for as much as 2 hours-Some whales can make even more impressive dives

Store large amounts of oxygen (twice as much as humans)-Store it in blood and muscles-About 36% of our total oxygen is in our lungs and 51% is in our blood-Weddell seal holds only about 5% in lungs while stockpiling 70% in blood-It has twice the volume of blood per kg of body mass as a human

Weddell seal has a huge spleen-The spleen can store about 24 L of blood.

High concentration of myoglobin (an oxygen-storing protein) in their muscles-Store about 25% of its oxygen in muscle, compared to only 13% in humans

Conserve oxygen-Swim with little muscular effort-Use buoyancy changes to glide passively upward or downward-Heart rate and oxygen consumption rate decrease during a dive-Blood is routed to the brain, spinal cord, eyes, and adrenal glands-Blood supply is altogether shut off to muscles during the longest dives-Derive their ATP from fermentation after deplete oxygen stored in myoglobin