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Circulation, gas exchange, osmoregulation, and excretion (Cardiovascular…

- - - - 2 basic adaptations
        
        simple body plan that places most or all cells in contact w/ environment
        
        gastrovascular cavity
        
        found in hydras, cnidarians, platyhelminthes, and jellies
        
        fluid bathes inner and outer tissue layers
        
        works to minimize diffusion distances
        
        a circulatory system
        
        contains three basic components
        
        circulatory fluid
        
        set of interconnecting vessels
        
        muscular pump (heart)
        
        open vs closed
        
        open
        
        circulatory fluid called hemolymph
        
        contraction of heart pumps hemolymph throughout body
        
        sloshes around with movement
        
        closed
        
        circulatory fluid called blood
        
        blood is confined to vessels
        
        heart pumps blood throughout vessels and has smaller branches that get into organs
- - - - blood flows from heart to the body and back to the heart
    - - two circuits of blood flow
        
        one goes to site of gas exchange and back into the heart
        
        one goes from heart to the rest of the body and back to the heart
  - - - one atrium and ventricle #
        
        useful if you have efficient gas exchange sites (gills of fish)
        
        mainly uses movement to help circulate blood
      - two atria and one ventricle #
        
        two pathways away from heart, one to gas exchange site and other to the rest of the body
        
        efficient if blood flow to lungs are cut off to conserve energy
        
        not very efficient at getting O2 rich blood to the rest of body because of one ventricle
      - two atria and two ventricles
        
        efficient at moving large quantities of materials
        
        septum that separates the ventricles keeps O2 poor blood from O2 rich blood
        
        found in birds and mammals
    - - Contraction of right ventricle sends blood to lungs
      - blood goes to capillaries in the lungs and unloads CO2 and loads O2
      - blood returns to the left atrium via pulmonary veins
      - blood flows from the LA to the left ventricle
      - heart contracts and pumps oxygenated blood throughout the rest of the body
      - O2 rich blood unloads at capillary beds in organs and loads CO2
      - O2 poor blood flows back to right atrium via the superior and inferior vena cava
    - - cardiac cycle- one sequence of pumping and filling
      - systole- contraction phase
      - diastole- relaxation phase
      - cardiac output- vol. blood/min
      - heart rate- beats per minute
      - stroke volume- vol. of blood pumped in one stroke
      - ECG/EKG- measures electrical activity of the heart
      - bundle branches- send electric signal down the septum
      - purjenke fibers- send electric signal up wall of heart
      - SA node- located in right atrium, start of the electric impulse to contract heart
      - AV node- relay point to conduct impulse from SA node
    - - Heart disease
        
        prominent in the US because of sedentary lifestyle and bad diets
        
        atherosclerosis: hardening of arteries by accumulation of fatty deposits (increases blood pressure)
        
        HDL cholesterol- scavenges excess cholesterol
        
        LDL cholesterol- delivers and stores cholesterol as fat
        
        cause of myocardial infarction- blockage of arteries from plaue or thrombi
        
        hypertension- constant high bp that causes breakdown of arterial wells and promotes plaque buildup
        
        increase risk- bad diet and little to no exercise
        
        decrease risk- exercise regularly and eat healthy food
        
        heart disease increased in baboon populations in African National Parks because they eat the leftover junk food that humans leave behind
      - breakups lol
  - - - artery
        
        thick and elastic
      - vein
        
        not as thick or elastic
      - explanation
        
        artery is thick and elastic to handle the high velocity of blood pumped from the heart
        
        veins aren't as thick because they don't handle the high blood pressure from the heart contraction. instead they have valves to prevent backflow and that's what they use in times of low blood pressure
        
        might fail if the valves weaken
    - - measured by using blood pressure cuff
      - normal reading is 120/80
      - measured as systole/diastole
      - both pressures are measured in mmHg
      - blood pressure changes every time we sit, stand, or lay down throughout the day because our hearts work against gravity to push blood to the brain
      - high bp is 140/90
      - Hypertension dangerous b/c it causes blood clots
    - - role is to get O2 to tissue
      - not very big
      - arteriole constriction or dilation or precapillary sphincters can alter blood flow
      - dilation beneficial to exchange faster
      - constriction beneficial to transfer O2 to body parts that need it more
      - exercise needs dilation and not using muscles can use constriction
      - leaks
        
        movement of fluid out of blood vessels is caused by bp
        
        moves to interstitial fluid
        
        called plasma at this point
        
        fluid goes to lymphatic system
        
        contraction of vessel walls and skeletal muscle contraction causes lymph to move around
        
        if it doesn't go back to bloodstream, edema forms
        
        worms that block flow of fluid causes elephantiasis
        
        swollen glands are the result of an increase in white blood cell production
- - - - water- solvent
      - ions- osmotic balance, pH buffering, and regulation of membrane permeability
      - plasma proteins
        
        albumin- osmotic balance, pH buffering
        
        antibodies- defense
        
        apolipoporteins- transport
        
        fibrinogen- clotting
      - substances transported by blood
    - - Leukocytes (WBCs)- defense and immunity
        
        basophils, lymphocytes, eosinophils, neutrophils, monocytes
      - platelets- clotting
      - erythrocytes (RBCs)- transportation of O2 and some CO2
        
        last for 120 days
      - produced in bone marrow
      - sickle-cell disease
        
        abnormal form of hemoglobin distorts the shape of the RBC
        
        prevents efficient delivery of O2, CO2, and metabolic waste
        
        can get it if parents are both carriers and you are born with both recessive alleles
        
        still persists in populations where this protects from certain diseases (e.g. malaria)
- - - - gills are better in water, lungs are better out of water
- - - - negative pressure pulls air in rather than pushing air in (pressure goes from high to low)
    - - medulla gets signals from vessels and detects decrease in pH of cerebrospinal fluid
      - signals from medulla to rib muscles and diaphragm make you breathe harder (get rid of CO2 faster)
      - blood CO2 levels fall and pH rises
      - carbonic acid bicarbonate buffer system helps maintain neutral blood pH
- - - - number of moles of solute per liter of solution
      - two solns. w/ same osmolarity- isoosmotic
      - soln. w/ higher concentration than other soln- hyperosmotic
      - more dilute soln. - hypoosmotic
      - water flows from hypoosmotic to hyperosmotic
  - - - ammonia- most common in aquatic species and release by diffusion
      - urea- low toxicity, high energy cost, mostly formed by terrestrial animals
      - uric acid- even more energy needed than urea; insects, land snails, and mostly reptiles form it
  - - - be an osmoconformer
        
        be isoosmotic with surroundings
        
        all osmoconformers are marine animals
        
        no tendency to gain or lose water
      - be an osmoregulator
        
        control internal osmolarity independent from environment
        
        freshwater or terrestrial animals
        
        in hypoosmotic environment, osmoregulator discharge excess water
        
        hyperosmotic environment, take in water
    - - goal is to not get dehydrated since animals not living in water
      - more dehydrated, higher osmolarity, more solute concentration in body and in excretion
      - less dehydrated, less solute concentration, pee more
    - - goal is to keep internal solute concentration hyperosmotic to their environemnt
      - releases a lot of dilute urine
      - intakes little water but more salt
    - - constantly lose water by osmosis
      - constantly drinking water
      - eliminating urea is priority because it can denature proteins
    - - they're cool
      - anhydrobiosis - dormant state of tardigrades when environment dries up
      - they can be dormant for a long time and just come back to life when conditions are right
    - - water goes where salt goes
    - - special salt glands in nose help secrete high concentration of sodium
      - salt glands create a net gain of water
      - humans can't drink saltwater because it takes more water to level solute concentration thus causing a net loss of water
- - - - fluid then becomes the filtrate
  - - - have dead end tubules with beating cilia inside that filters and releases urine
    - - nephridia is immersed in coelomic fluid, ciliated funnel brings waste to collecting tubule that releases waste
    - - tubes are immersed in hemolymph, there's no filtration, transport epithelia that lines tubules secretes certain solutes
    - - function in both osmoregulation and secretion
        
        secretion includes the distal tubules and the collecting ducts
      - tubules of kidneys are associated with network of capillaries
      - each kidney has outer renal cortex and inner renal medulla
      - excretory tubules carry and process filtrate produced from blood entering kidney
      - most fluid in filtrate is reabsorbed
      - remaining fluid leaves excretory tubules as urine and is collected in the inner renal pelvis and exits kidney via uterer
      - on renal cortex and medulla, nephrons are spread out
      - 85% are cortical nephrons and remainder are juxtamedullary nephrons
        
        juxtamedullary nephrons are essential for production of urine
- - - - reabsorption is critical for recapture of ions, water, and nutrients from huge volume of beginning filtrate
      - NaCl is transferred via active transport
      - when salt moves from filtrate to interstitial fluid, water follows by osmosis
      - other essential substances are actively and passively transported from filtrate to interstitial fluid
      - H+ is trapped to form NH4+
    - - filtrate flows to loop of Henle which reduces filtrate volume even more
      - water channels formed by aquaporin proteins make transport epithelium freely permeable to water
      - deeper in the medulla you go, the saltier it gets
    - - has transport epitheluim that lacks water channels
      - thin segment excretes NaCl to balance osmolarity in medulla
      - thick segment has epithelium sends NaCl out causing filtrate to become dilute
    - - regulates K+ and NaCl concentration and pH by controlled secretion of H+ and reabsorption of HCO3-
    - - processes filtrate to urine