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(Gas Exchange Occurs Across Specialized Respiratory surfaces (Mammalian…

- - - - parapodia serve as gills/swimming/crawling
    - - long feathery gills covered by an exoskeleton
      - specialized appendages drive water over gills
    - - gills are tubular projections of the skin
      - gas exchange occurs by diffusion
      - fluid in coloem circulates
    - - mainatains partial pressure of CO2/O2
      - to promote ventilation animals move gills through water or water over gills
      - crayfish/lobsters: paddle-like appendages drive current water over gills
      - mussel/clams: move water with cilia
      - octopus/squid: take in and eject water
      - fish: use motion of swimming, water passes over gills
        
        countercurrant exchange: exchange of a substance or heat between 2 fluids flowing in opposite directions
        
        helps efficiency in gas exchange
        
        blood and water flow in opposite direction
- - - - smoothness minimizes resistance of fluid flow
    - - endothelium
      - basal lamina: extracellular layer
      - exchange between blood and the interstitial fluid
      - smallest blood vessel with thin porous walls
    - - 2 layer of tissue surrounding epithelium
      - outer layer: connective tissue made of elastic fibers, collagen
      - next layer: made of smooth muscle and elastic fibers
      - walls are thick, strong, and elastic
      - maintains blood pressure and flow to capillaries
      - smooth muscles helps regulate blood flow path
      - signals form nervous system/hormones dilate/constrict blood flow to diff body parts
    - - transport blood back to heart
      - lower pressure
      - thin walls
      - contains inner valves: maintains unidirectional flow of blood
  - - - flows from high to low pressure
      - contraction of ventricle=blood pressure
      - blood floes away from heart which is at a higher pressure
      - the recoil of the arterial walls maintains blood pressure
      - once blood enters arterioles/capillaries flow slows down
    - - diameter
      - blood slows down as it moves from arteries to arterioles and then to capillaries
      - increased cross sectional area=decrease in velocity
  - - - diastolic pressure
      - systolic pressure
    - - cuff deflates gradually when pressure from the cuff s just below of artery, blood pulses into forearm making sounds heard of a stethoscope=systolic pressure
      - cuff further deflates until blood flows freely and sounds disappear = diastolic pressure
      - cuff is inflated until pressure closes artery= no blood flow past cuff, pressure from cuff is more than artery
    - - systemic circuit: 120 mm Hg
      - systole: 70 mmHg
      - pulmonary circuit is 6-10x lower
    - - when you stand the arterial BP in brain is 27 mmHg less than heart
      - fainting is a response triggered when nervous system detects BP in brain is to low so body collapse to ground placing head and heart at the same level increasing the amount of blood flow to the brain
      - animals with long necks overcome gravity
        
        systolic pressure is high near heart
        
        when head is lowered cardiac output is released and it has a reduced blood pressure in brain
      - flow in legs
        
        gravity impedes upward flow of blood
        
        the low BP in valves maintain the unidirectional flow in veins
        
        rhythmic contractions of smooth muscle/skeletal also help delver blood to heart
      - after exercise it is recommended to do a cool down to gradually slow down the body with the heart
  - - - open/closing controls blood flow
    - - chemicals produced locally
      - hormones traveling through blood stream
      - nerve impulses
    - - BP drives fluid out of capillaries
      - Blood proteins pull fluid back in, and many are to large to pass
  - - - inside is a honeycomb of connective tissue filled with WBC
      - when fighting infection WBC multiply and lymph become swell/tender
      - body defense
- - - - buffer blood
      - maintain osmotic pressure
    - - buffer againts pH changes
      - maintains osmotic balance between blood and interstitial fluid
      - combat viruses
      - help lipid travel
      - transit nutrients, metabolic waste, respiratory gases and hormones
  - - - red blood cells: transports O2
      - white blood cells: function in defense
    - - pinched off cytoplasmic fragments of specialized bone marrow
      - no nuclei
      - serve both structural/molecular function in clotting
    - - most numerous
      - biconcave: small disc shape that is thinner in the center than edges enhancing its function
      - shape increases surface area, and the rat of O2 diffusion
      - mature lack nucleus(more room for O2 consumption)
      - hemoglobin: iron containing protein that transports O2
        
        lack mitochondria
        
        anaerobic to produce ATP (making it more effective)
        
        bind to O2 in lungs/gills by diffusion into hemoglobin
      - sickle cell disease: abnormal form of hemoglobin
        
        occurs from alteration of amino acid sequence of hemoglobin at a single position
        
        changes the shape of hemoglobin causing it to lodge into capillaries not transporting O2 rest of body
        
        cells eventually rupture reducing number of RBC
    - - there are 5 major types
      - fight off infection
      - some are phagocytic: engulf microorganisms
      - lymphocytes: mount immune responses against foreign substances
      - found in the circulatory/lymphatic system and the interstitial fluid
  - - - 1 will be the stem cell
      - 1 will be given a specialized function
        
        Erythrocyte
        
        Leukocyte
        
        Platelets
    - - Lymphoid Progenitor cells: produce Lmphocytes
        
        B Cells
        
        T cells
      - Myeloid Progenitor: cells that produce cellular elements
        
        WBC
        
        RBC
        
        T cells
      - Starts of at the stem cell
  - - - Thrombin: converts fibrogenin to fibrin
      - forms threads
    - - Prothrombin -> Thrombin
      - positive feedback
      - Fibrinogen->Fibrin
  - - - healthy arteries have smooth inner lining that reduces resistance to blood flow
      - atherosclerosis: damage/ infection roughening the lining which hardens arteries; fats accumulate
      - cholesterol is a major key player in atherosclerosis
      - LDL: low density lipoprotein delivers cholesterol to cells fr membrane production
      - HDL: high density lipoprotein, scavenges excess cholesterol for return to liver
      - inflammation is the damage done to the arterial lining
      - plaque: a fatty deposit grows steadily incorporating fibrous connective tissue and cholesterol
        
        if ruptured thrombus can for in artery
        
        heart attack: mycardinal infarction
        
        damage/death to cardiac muscle tissues from blockage of coronary arteries
        
        if large enough portion gets blocked the heart can stop
        
        stroke: death of nervous tissue in the brain due to lack of O2
        
        extent depends on location
        
        a drug can dissolve a block caused by the thrombus
      - there are not many warning signs until symptoms are critical
        
        pectoris: partial blockage of coronary arteries causing occasional chest pains, signaling parts of heart are not receiving enough O2
        
        obstructed artery: treated surgically by inserting a mesh tube=stent to expand artery
    - - it can be inherited
      - strongly influenced by lifestyle
      - excersize decreases the LDL/HDL ratio reducing cardiovascular disease
      - smoking and trans fats can increase cardiovascular disease
    - - HBP damages epithelial walls=plaque formation
      - systolic pressure= above 140 mmHg
      - diastolic pressure: above 90 mm Hg
      - can be controlled by a set diet
- - - - enables animals to live in environments where osmoconformers could not
      - move from marine to freshwater
      - allows marine animals maintain internal osmolarity diff from seawater
    - - osmolarity is same as seawater
      - gain water and salt ions from food/water
      - lose water by osmosis
      - excess salt is excreted from gills
      - excretion is importation for proteins to not denature from high concentrations of urea
        
        sharks(exception): they have a TMAO produced by tissues that protect protein from urea
    - - body fluids are hyperosmotic: cells cant tolerate low salt concentration
      - salts lost by diffusion are recovered by eating and salt uptake across their gill
      - water balance relays on excretion of large amounts of very diluted urine/drinking no water
    - - anhydrobiosis: adaption where animals enter dormant stage when their habitats dry up
      - maintaining high amounts of glucose prevent it from drying out
    - - adaptions are key to prevent water loss
      - waxy covering
      - dead layer of skin
      - lose water in many ways: urine/feces/across skin
      - maintain water balance by eating/drinking
      - produce water by cellular respiration
  - - - little salt appears in urine
      - fluid dripping at top of nose is conc with NaCl
- - - - actual exchange happens over over short distances
  - - - Porifera
      - Cnidaria
    - - minimizes diffusion distance
      - increses surface area
  - - - the circulatory fluid is called hemolymph also acts as the interstitial fluid
      - Arthropods/Mollusks/Clams
      - exchange happens with the sinuses
    - - blood is the circulatory fluid and it has a separate one for its interstitial fluid
      - heart pumps blood through vessels that branch into smaller ones into organs and tissues
      - Chordata/Annelids
      - exchange occurs between blood and interstitial fluid
    - - set of interconnecting vessels
      - muscular pump: heart
        
        powers circulation
        
        uses metabolic energy to elevate circulatory fluid/hydrostatic pressure
        
        connects aqueous environment of body cells and organs that exchange gas/nutrients/dispose of waste
      - Circulatory Fluid
    - - lower hydrosatic pressure usually associates with open circulatory systems
        
        uses less energy
        
        some use hydrostatic pressure for movement
      - closed circulatory systems
        
        regulates blood distributions
        
        uses energy to pump and deliver nutrients and waste to proper locations
  - - - blood circulates to/from heart through network of vessels
      - blood circulates to and from heart through a network of vessels
    - - Veins
        
        venules: downstream end of capillaries that converge into veins
        
        Veins: vessels that carry blood back to the heart
      - Capillaries
        
        microscopic vessels with thin porus walls
        
        capillary beds; netwrok of capillaries that enter tissues
        
        across thin walls dissolved gases/nutrients/waste are exchanged by diffusion between blood and interstitial fluid
      - Arteries
        
        carries blood from heart to organs throughout body
        
        arterioles: small branches within organs that deliverer blood from heart
      - blood flows in 1 direction
      - veins and arteries can be distinguished by the direction they carry blood
        
        veins return blood to heart away from capillaries
        
        arteries carry blood away from heart to capillaries
        
        Exceptions; Portal Veins which carry blood between pairs of capillary beds
        
        hepatic portal vein: carries blood from capillaries in digestive system to capillaries in the liver
    - - atria: receive blood entering heart
      - ventricles: pump blood out of heart
      - stricture+function=natural selection
    - - blood travels through body and returns to starting point in a single circuit
      - sharks/rays/bony fish
      - heart with 2 chambers
        
        atrium; blood entering heart collects here before being transferred to the ventricle
        
        ventricle; contraction pumps blood to capillary beds in gills
        
        blood enters veins back into heart
        
        diffusion of O2 into blood and CO2 out of blood
        
        O2 rich blood carried through body
      - traves between 2 capillaries before returing to heart
      - flows under reduced pressure
    - - 2 circuits of blood flow; pumps for 2 circuits are combined into 1 heart
      - simplfies coordination to having both pumps into 1 hart
      - Right side
        
        pumps oxygen poor blood into capillary beds of gas exchanging tissue
        
        pulmonary circuit: gas excahnge in lungs (reptiles/mammals)
        
        pulmucotaneous circuit: in amphibians because gas exchange occurs in lungs/skin
      - Left side
        
        pumps O2 enriched blood from gas exchange tissues to capillary beds of organ tissues
        
        after exchange of nutrients and O2, O2 poor blood returns back to heart
        
        systemic circuit
        
        has higher blood pressure
      - allows high flow of blood to brain /organs/tissues
      - Evolution
        
        some have intermittent breathing; periodically filling their lungs, passing long periods w/o gas exchange or relying on other forms of gas exchange
        
        reptiles/amphibians
        
        adaptations in intermittent breathing enables circulatory system to bypass lungs
        
        Frogs/Amphibians
        
        3 chambered heart
        
        2 atria
        
        1 ventricle
        
        ridge within ventricle separates 90% of flow
        
        incomplete separation allows shut off of blood flow to lungs
        
        skin=gas exchange site
        
        Alligators/Crocodiles
        
        ventricles are divided by a complete septum
        
        pulmonary: connect where arteries exit heart
        
        connection allows arterial veins to stop blood flows away from lungs when under water
        
        Turtles/Snakes/Lizards
        
        3 chambered heart
        
        incomplete septum that semi-separates a single ventricle into right and left chambers
        
        Arteries(Aortas): lead the systemic circulation and regulates blood flow
        
        Birds/Mammals
        
        differ form any other vertebrate
        
        2 atria
        
        2 divided ventricles
        
        left:(recives/pumps )rich blood
        
        righ: recives/pumps O2 poor blood
        
        cant vary blood flow to lungs w/o varying blood flow throughout body in a parallel fashion
        
        shaped by natural slection
        
        endotherms use 10x more energy
        
        4 chambared heart is due to convergent evolution
- - - - active
    - - passive
    - - inner: adheres to outside of lung
      - adheres to wall of thoracic cavity
    - - regulated by medulla oblongata
        
        establishes rhythm
        
        breathing control canter
      - regulated by involuntary mechanisms
      - homeostatic control
        
        pH levels fall due to rising levels of CO2
        
        medulla senses drop and signals respiratory system
        
        ventilation is increased
      - negative feedback keeps lungs from over expanding
- - - - found on each segment
      - beating cilia draws material in tube
    - - excretory
      - osmoregulation
  - - - found in vertebrate/some chordate
      - osmoregullation/excretion
- - - - 2 verntricles contract almost in unison and pump some blood
      - volume of systemic circuit is bigger than pulmonary
  - - - then flows into ventricles while all 4 chambers are relaxed
      - the remainder is transferred by contractions of the atria before ventricles contract
    - - left has stronger contractions b/c blood pumps via systemic circuit
      - left and right pump the same volume of blood
    - - relaxed: chambers fill with blood
      - contraction: blood gets pumped
    - - systole: contraction phase
      - diastole: relaxation phase
      - Ventricular Systole and Atrial diastole: remainder of cycle ventricular contraction pumps blood into large arteries through semilunar valves
      - Atria systole and ventricular diastole : brief period of atrial contraction forces all blood remaining in the atria into ventricles
      - 1.Atrial and Ventricle Diastole: during relaxation phase, blood returning form large vein flows to atria and then to ventricles through the AV valves
    - - heart rate: number of beats per minute
      - stroke volume: amount of blood pumped by ventricle by 1 contraction
        
        average is about 70ml
    - - valves=flaps of connective tissue open when being pushed to one side and close when pushed from another side
      - semilunar valves: are located at 2 exits of heart: where pulmonary artery leaves the right ventricle and where the aorta leaves left ventricle
        
        pushed open by pressure generated during ventricle contractions
        
        ventricles are relaxed, blood pressure builds up in pulmonary artery and aorta close the semilunar valves and stops backflow
      - atrioventricular valve (AV): between the atrium and the ventricular
        
        pressure from ventricular contractions closes AV valves stopping blood from flowing back to atria
        
        anchored by fibers that hold them from turning inside out
    - - 1st sound= recoil of blood against closed AV
      - 2nd sound= by vibrations from closing the SV
    - - infection
      - birth defect
  - - - some cells are autorhythmic=contract without signals from the nervous system
      - each cell has its own contraction rhythm
    - - impulses from SA spread rapid;y because they are coupled throughout gap junctions
      - impulses can be measured when it reaches body fluids/skin
      - produces electrical impulses
    - - 1.signals from SA node spread through walls of atria, both atria contract in unison
      - Signals are delayed at the AV node
      - Bundle branches pass signals to the heart apex
      - signals spread to ventricles
      - atrioventricular node(AV): a relay point where impulses are delayed for about 1 second before spreading throughout the heart
        
        delay allows atria to completely empty before ventricles contract
        
        AV signals are conducted to the heart apex and throughout ventricular walls with bundle branches & Purkinje fibers
    - - sympathetic division: speed up pacemaker when activity has begun:increases heart-rate and additional O2 is proved to muscles
      - parasympathetic division: when relaxed slows down the pacemaker decreasing heart rate and conserving energy
      - hormones also affect pacemaker
      - temperature also affect pacemaker