Model organism - VERTEBRATE... Organisms having a SPINAL COLUMN or BACK BONE...
                                                       a dorsal (along the back) set of nerves encased in bones. 
  
     Verts... are members of phylum Chordata that includes most complex animals on Earth.
                 some 50,000 species:  including amphibians, fishes, reptiles, birds, & humans, 
                        all with segmented spinal column & a distinct, well-differentiated head*. 
 
                         vertebral column - a winning evolutionary design resulting in fastest runners,
                                                       highest fliers, deepest divers, most agile climbers,
                                            and the best 150 students that ever lived...

  
Vertebrate Physiology...  lies in what the tissues of the major organs can do,
   at the cellular level physiology lies in: 4 Fundamental tissues common to vertebrates

   1.  EPITHELIAL - sheets of tightly packed cells that line body cavities* & organ surfaces
         -  ectodermal origin
         -  prevents dehydration - forms a permeability barrier [to prevent loss of H₂O]
         -  provide a sensory surface, as well as a secretory layer ₂
         -  typed by cell SHAPE*:   squamous,  columnar,  cuboidal,  stratified  (wolf & pics)
     

 2.  CONNECTIVE - mesodermal tissues that function to BIND & SUPPORT  pics    
 
      Adipose tissue - adipose (fat) cells*, which insulate the body & store fat energy
      Blood - includes fluid (non-solid) matrix for RBC & WBC's transport      (NHLBI)
                          ...plasma*  H₂O, salts, dissolved proteins  (hematocrit*)
                          ...cells      RBCs & WBC  (pics = lymphocytes - macrophages - a clot)
      Cartilage* - strong, but flexible skeletal material at end of bones made of
                          collagen & elastin fibers embedded in rubbery matrix chondroitin
      Bone - mineralized rigid connective tissue [NIH bone diseases site]
                          collagen fibers embedded with Ca⁺⁺, Mg⁺⁺, &  Pi salts for hardness
      Fibrous connective tissue - dense matrix collagen fibers*... polysaccharides, proteins, water
             forms   ...tendons - connects muscles to bone
                                ...ligaments - join bones to bones and together at joints
      Loose connective* - loose weave of fibrous proteins with lots blood vessels...
                                      binding & packing material holds organs & tissue in place
                       Summary figure of Connective Tissues

   
 Muscle & Nerve Tissue...
   
3.  MUSCLE... contractile tissue derived from mesodermal origins 
                        contains proteins actin & myosin = in filament (thread-like) form
                        multi-nucleate cells that assemble into fibers called myofibrils
                        human body has about 200 bones and more than 600 muscles
                        Muscle contractions shorten cell cell length & function to produce force & motion.
          3 kinds:     a)  skeletal...  striated appearance in microscopy - voluntary control
                           b)  cardiac...   striated, but branched, in heart - involuntary control
                           c)  smooth...   in organ walls, non-striated - involuntary
                                                 picture of types in a wolf* & in a chimp*
                                                 role of skeletal muscles & tendons* in human body

4.  NERVE...  tissues made of cells that conduct electrical impulses for communication
                      have an ectodermal origin.
          2 kinds    a)  neurons* - electrically excitable cells of nervous system
                         b)  glial cells* (astrocytes - pic)-  non-conducting cells that
                                                 surround, support, insulate, & protect neurons
     
                  summary figure of vertebrate tissues
 

ORGANS - systems made of the 4 tissue  types above (& some others), 
                      which catalyze a physiological process (some specific function)

                 The eleven main vertebrate animal ORGAN SYSTEMS...         Table

                 ... are the subject matter of Biology 360 - Comparative Physiology:
                                                       animal and plant physiological processes.

                        Organs on Demand    &   3D-printing (tissue engineering)

                    SKIP ALL THE MATERIAL ABOVE THIS POINT

Part 3:   VERTEBRATE  PHYSIOLOGY...  to apply some concepts we've seen so far:     Vertebrate Physiology is the study of how vertebrates function, often measured by...     Metabolic Rate - total energy used by organisms per unit time, in doing biological work.
	Animal Bioenergetics...                    energy needed to do vertebrate physiology:                                                   to walk, run, swim, or just to be...
How does one measure energy metabolism?  i.e.,  the METABOLIC   RATE  (MR)...      measured in calories  =  amt of Heat Energy                               1c  = energy required to raise 1g water 1oC  [14.5o to 15.5o C]  1c = 4.2 joules                                   1C = energy required to raise 1 kilogram of water  (1C = 1Kc)                         ?   minimal  Cal  -->  the energy required for basic functions of life (to be)                       ?   maximal Cal  -->  for peak metabolic activity --> Olympic swimmer   * Let's link Cell respiration (Krebs & ETC) to Metabolic Rate                                  by determining O2 consumption reported as  VO2MAX             glucose --->  CO2 + NADH + FADH2 + ATP ---e--->  O2 + H ---> H2O             oxygen consumption is thus related to rates of cell respiration (exercise)

VO2max...  is determined using 'stress' measuring equipment such as...                     respirometer*,    oxygen meters,    a cycle ergometer*,          tread*mill or bike   or  measuring VO2max [even in swimming]*.

Vertebrate Physiology or the Science of Physiology...      often monitors... VO2 max [Metabolic Rate] as influenced by many variables  as...                                 age,  sex,  body size,  temp,  food levels, disease state,                                time of day, size of organism,  hormonal balance,  available O2

BMR - basal metabolic rate - heat calories used @ rest w/o stress by endotherms                 ex: humans -   males   1,600 - 1,800 Kc/d     females   1,300 - 1,500 Kc/d

athletes are often naturally selected for their sports due to unique                  anatomy/physiology, as well as their aerobic capacity:           Michael Phelps:      is he a perfect swimmer?                   -  he expended 4,000 Kc during workouts (he ate 12,000 Kc/day in training)                   -  wide wing span of 79" (wider than he tall at 76")                   -  inseam of only 32" (short legs) & long torso = rides high in water                   -  size 14 'flippers'- 15 degree further ankle bend than most swimmers                   -  wide shoulders, yet slender hips                   -  double jointed elbows/knees = flex with an exaggerated range of motion                   -  stroke volume 600 ml per vent./beat =  30 L/min (8 gal/min = 2x avg male)                   -  lactate levels = 5.6 mM/L is ½ that of many elite  swimmers.                   -  and maybe most importantly excellent stroke mechanics.

   Much of vertebrate metabolic energy is used to maintain...  HOMEOSTASIS... 
                 i.e., regulating the internal 'cellular' environment of vertebrates.
                        maintaining a steady state internal constancy of condition
                                 in the face of a changing external environment [figure*]

        PHYSIOLOGICAL COMPENSATION...  short term physiological adjustments 
              or adaptations to environmental changes, i.e., homeostatic compensation

        Internal "Milieu" - (Claude Bernard - Fr. 1880's)... observed the interstitial fluids 
        (the spaces between cells) which exchange nutrients with the blood are very stable:
 
                          the Constancy of Human milieu includes...
  
                                    pH of blood           7.4      +   0.1
                                    body temp           37^o C   +   1^o C
                                    blood sugar          0.1%        [mg% - 100 mg/100ml blood]

 

Homeostatic Regulation:
       now let's look at some of the mechanisms that cells have evolved to maintain constancy
       or the processes of Physiological Compensation.
  
        a Homeostatic Regulator*  mechanism has 3 parts... (ex: a heating system)
                  1.   receptor ....         detects a change...                  thermometer
                  2.   controller ...        processes info...                       thermostat responds 
                  3.   effector .....         produces a response...            heater/chiller
                                                                                                                    * (not unlike signal transduction*)
     
   Examples of Homeostatic Regulation... (Physiological Compensation Mechanisms)

   1.  Temperature         
              Room temperature controllers - see model* -
 
              How a body warms/cools:       heat transfers from warmer body to a cooler one
                                                          body temperature thermoregulation* 
  
              Human mechanism: in verts hypothalmus regulates body temperature by linking
                                 nervous & endocrine system in homeostatic thermoregulation...  fig 40.17*
 
   
 

  
 2. pH regulation of the blood 
       pH 7.4  +  0.1      continuous blood pH below 7.0 can be fatal.
           Andromeda Strain (TV-2008) - original story by Michael Crichton
                - virulent space microbe infects town's people...
                - microbe has crystalline structure & lacks DNA, RNA, & proteins,
                - all die by lethal blood clotting; growth curve of microbe = narrow pH range,
                - only 2 survived the microbe...  why? 
                          microbe grows only pH 7.35 - 7.45 (human blood pH range)
                          a crying baby - blows off CO₂ - reduces blood acidity = alkalosis  (pH > 7.45)
                       & a drunk (Sterno) - bleeding stomach ulcers - favors    = acidosis   (pH < 7.35)
   
     carbonic* anhydrase - CO₂ + H₂O   <--CA-->   H₂CO₃   <--->  H⁺ + HCO₃^-  
                                                                                             carbonic acid                             
       Hemoglobin pick up H⁺ ions... buffering blood cells  &  CO₂  exhalation

            buffer:     a substance, as HB & other proteins, that in solution tends to stabilize the
                           hydrogen-ion concentration by neutralizing, within limits, both acids and bases
                           if pH in blood cells drop [H+ ^] then carbonic anhydrase
                           HCO₃^-  +  H⁺ shifts ---> to   H₂CO₃  which dissociates & vice versa
             Seawater Acidification*        oysters and seawater acidification video

  
     3.  Calcium homeostasis   (in blood - normal range is 9 to 11 mg%)

              Ca⁺² is needed for nerve function, muscle contraction, blood clotting, etc. 
                      calcium regulation functions via antagonistic hormones*,
                      a common theme in homeostatic regulations...
   
                                thyroid makes -->   calcitonin hormone - lowers Ca levels
                                           causes Ca to be deposited into bone
                                           reduces intestinal absorption of Ca
                                           reduces Ca uptake by kidney
  
                                 parathyroid -->  parathyroid hormone - raises Ca levels
                                          stimulates release Ca from bone
                                          increase Ca uptake by intestine & kidney       

          Calcium concentration is a delicate interplay between antagonistic hormones.  

 4. Blood Glucose balance -  (80-110mg/100ml)
                                      
             Pancreas makes insulin and glucagon, which also function as antagonistic hormones

                 How glucose homeostasis works*  and

                  How do insulin & glucagon function as signal molecules*

                              Animation of Glucose Homeostasis*^view@home    
                              (Am. Diabetes Assoc. & its diseases): 

            Insulin promotes cellular uptake of glucose into liver, muscle, and fat cells.
            Glucagon promotes the hydrolysis of stored glycogen in the liver and fat in adipose tissues.
   
           glucose level is a delicate interplay between antagonistic hormones (Insulin & Glucagon) 
 
    Key Concepts*   
                   back          copyright c2021         
                                 next            Charles Mallery,    Biology 150, Department of Biology, U. of Miami,  Coral Gables, FL 33124

' SKIP the Material Below and go to Major Vertebrate Tissues'
Chord'ates are characterized by a stiff (flexible) cord, notochord*, running dorsally.
  dorsal nerve cord - SPINAL CHORD - is a tube of nerve tissue, runs dorsal to notochord
  
  notochord - solid, flexible rod of cartilage,  provides internal support,
                                                                           runs from brain to tip of tail. 
      in some chordates, the  notochord  is replaced by a BONY vertebrate column... 
      making subphylum Vertebrata, a primary division of the phylum Chordata
  
            evolutionary innovations of CHORDATES:   [Cambrian Explosion]    
                  evolved 542-488 million years ago* - basic body plan of most animal phyla established:
                   bilateral symmetry        repetition of parts on opposite sides of an axis
                   cephalization                 presence of a head
                   notochord & spinal cord  dorsal cords of cartilage & nerve tissue
                   gill slits                         pair of openings through pharynx (vestigial in birds & mammals)
                   tail                                present throughout life (vestigial in human embryos only)
                   a fully lined body cavity thoracic and abdominal cavities lined by epithelia
                   a complete gut tube        coelom - fluid cavity formed from mesoderm
                   segmented development   in larva or embryo development myomeres flank notochord
                                                gives rise to muscles & bones
  
    
          

the VERTEBRAL members of chordate family have a number of similarities... 

         all have same basic body plan & same sort of organs [liver, kidney, pancreas] including:

           skeleton - with bony skull (cranium) surrounding brain    figure 49.26*
               jointed bones - ball & socket, hinge, & pivot joints    
               vertebrate column* surrounding a dorsal nerve cord
               coelom... internal tube which runs from mouth to anus (digestive system)
                              lined with mesoderm cells;  usually there are 2 cavities: 
                                     a) thoracic cavity* -holds heart & lungs of verts
                                     b) abdominal cavity* -holds stomach, intestines, & liver   

  
      mammals... organism that maintain same body temperature regardless of environment,
                         have hair, and females that nurse their young.
      primates... vertebrate organisms with 5 grasping fingers/toes, eyes at front of head,
                        a large brain, & fingernails instead of claws.
  
     model vertebrate might be ourselves - the human...
         - humans are  Endotherms...  warm blooded verts,      
                                      animals that regulates internal temperature at some constant value
                          vs.  Ectotherms...  cold blooded verts,  
                                         many vert animals use environmental energy to regulate temp
                                       [ i.e., snakes, lizards, amphibians, fish, etc = ectotherms]  figure*
   
    but our human model is more distinct...
            some of our model human vertebrate's more unique characteristics include:
                           - humans have hair instead of scales & feathers, as in most verts,
                           - humans have a birthing process, instead of laying eggs,
                           - humans have at least 210 cell types in their body   [human histology]