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Circulation, gas exchange, osmoregulation and excretion (Exchange surfaces…

- - - - simple body plan that places most or all cells in contact with environment
        
        gastrovascular activity
        
        fluid bathes inner and outer tissue layers
        
        works to minimize diffusion distance
        
        found hydras, cnidarians, platyhelminthes, and jellies
      - circulatory system
        
        open vs closed
        
        open
        
        contraction of the heart pumps hemolymph throughout body
        
        sloshes around with movement
        
        circulatory fluid called hemolymph
        
        closed
        
        heart pumps blood throughout vessels and has smaller branches that get into organs
        
        circulatory fluid called blood
        
        blood is confined to vessels
        
        contains three basic components
        
        set of interconnecting vessels
        
        muscular pump (heart)
        
        circulatory fluid
- - - - 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
  - - - two atria and one ventricle
        
        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 ventrivle
        
        two pathways away from heart, one to gas exchange site and other to the rest of the body
      - 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
      - one atrium
        
        mainly uses movement to help circulate blood
        
        useful if you have efficient gas exchange sites (gills of fish)
    - - blood flows from the LA to the left ventricle
      - heart contracts and pumps oxygenated blood throughout the rest of the body
      - blood returns to the left atrium via pulmonary veins
      - O2 rich blood unloads at capillary beds in organs and loads CO2
      - blood goes to capillaries in the lungs and unloads CO2 and loads O2
      - O2 poor blood flow back to right atrium via the superior and inferiror vena cava
      - contraction of right ventricle sends blood to lungs
    - - 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 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
      - systole- contraction phase
      - cardiac cycle- one sequence of pumping and filling
    - - cause of myocardial infraction- blockage of arteries from plaue or thrombi
      - hypertension- constant high bp that causes breakdown of arterial wells and promotes plaque buildup
      - LDL cholesterol- delivers and stores cholesterol as fat
      - increase risk- bad diet and little to no exercise
      - HDL cholesterol- scavenge excess cholesterol
      - decrease risk- exercise regularly and eat healthy food
      - atherosclerosis: hardening of arteries by accumulation of fatty deposits (increase blood pressure)
      - heart disease in baboon populations in African National Parks because they eat leftover junk in food that humans leave behind
      - prominent in the US because of sedentary lifestyle and bad diets
  - - - measured by using blood pressure cuff
        
        normal reading is 120/80
        
        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, hypertension dangerous bc it causes blood clots
        
        both pressure are measured in mmHg
        
        measured as systole/diastole
    - - role is to not get O2
        
        not very big, arteriole construction or dialation or precapillary sphincters can alter blood flow
        
        dilation beneficial to exchange faster
      - leaks
        
        moves to interstitial fluid
        
        movement of fluid out of blood vessels is caused by bp
        
        called plasma
        
        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
    - - vein
        
        not as thick or elastic
      - explanation
        
        artery i 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 wweaken
      - artery
        
        thick and elastic
- - - - ions- osmotic balance, pH buffering and regulation of membrane permeability
      - plasma proteins
        
        antibodies- defense
        
        fibrinogen- clotting
        
        apolipoporteins- transport
        
        albumin- osmotic balance, pH buffering
      - water- slovent
      - substances transported by blood
    - - Leukocytes (WBCs)- defense and immunity
        
        basophils, lymphocytes, eosinophils, monocytes
        
        platelets- clotting
      - erythrocytes (RBCs)- transportation of O2 and some CO2
        
        last for 120 days
      - produced in bone marrow
      - sicke-cell disease
        
        abnormal form of hemoglobin distorts the shape of the RBC
        
        prevents efficient delivery of O2, CO2 and metabolic waste
        
        can get it 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)
- - - - fluid then becomes the filtrate
  - - - nephridia is immersed in coelomic fluid, ciliated funnel brings waste to collecting tubule that releases waste
    - - immersed in hemolymph, there's no filtration, transport epithelia that lines tubules secretes certain solutes
    - - have dead end tubules with beating cilia inside that filters and releases urine
    - - excretory tubules carry and process filtrate produced from blood entering kidney
      - most fluid in filtrate is reabsorbed
      - each kidney has outer renal cortex and inner renal medulla
      - remaining fluid leaves excretory tubules as urine and is collected in the inner renal pelvis and exits kidney via uterer
      - tubules of kidneys are associated with network of capillaries
      - renal cortex andmedulla, nephrons are spread out
      - function in both osmoregulation and secretion
        
        secretion includes the distal tubules and the collecting ducts
      - juxtamedullary nephrons are essential for production of urine
        
        85% are cortical nephron and remainder are juxtamentary nephrons
- - - - goal is to keep internal solute concentration hyperosmotic to their environment
      - releases a lot of dilute urine
      - intakes little water but more salt
    - - constantly lose water by osmosis
      - constantly drinking water
      - eliminating urea is priority bc it can denature proteins
    - - 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
    - - be an osmoconformer
        
        all osmoconformers are marine animals
        
        no tendency to gain or lose water
        
        be isoosmotic with surroundings
      - be an osmoregulator
        
        control internal osmolarity independent from environment
        
        freshwater or terrestrial animals
        
        in hypoosmotic environment, osmoregulator discharge excess water
        
        hypersmotic environment, take in water
    - - they're cool
      - anhydrobiosis- dormant state of tardigrades when environment dries up
      - can be dormant for a long time and just come back to life when conditions are right
    - - water goes where salt goes
    - - salt glands create a net gain of water
      - humans can't drink saltwater bc it takes more water to level solute concentration thus causing a net loss of water
      - special salt glands in nose help secrete high concentration of sodium
  - - - 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
- - - - neg. pressure pulls air in rather than pushing air in (pressure goes from high to low)
    - - signals from medulla to rib muscles and diaphragm make you breathe harder (rid of CO2 faster)
      - blood CO2 levels fall and pH rises
      - medulla gets signals from vessels and detects decrease in pH of cerebrospinal fluid
      - carbonic acid bicarbonate buffer system help maintain neutral blood pH