Principles of Biology: Exam 1

1. Chordates

   Nota:

   • Amniotic vs Anamniotic Amniotic: Reptiles, Mammals, Avians  Anamniotic: Amphibians, Osteichtyes (bony fishes), Agnatha (lampreys), Chondrichthyes (cartliginous fish)

1. Anthropods
2. Sponges
3. Cnidarians
4. Roundworms
5. Flatworms

   Nota:

   • lack a circulatory system and rely on diffusion for gas exchange *hence why they re flat, to reduce L, diffusion distance
6. Annelids
7. Echinoderms
8. Mollusks

Nota:

• internally generate heat to maintain body temp, temp stays steady regardless of environment Higher metabolic rates     

1. Birds and Mammals

Nota:

• depend on external heat sources, body temp changes w/ temp of environment lower metabolic rates *However, most ectotherms regulate body temp to some degree, most use behavioral methods, however, some use physiological methods

1. Reptiles, Fish, Amphibians
   1. Tunas (bony fish)

      Nota:

      • Elevate body temp by retaining metabolic rates with a COUNTERCURRENT heat exchanger
   2. Pelagic Sharks (cartilaginous fish)

      Nota:

      • Elevate body temp by retainig metabolic rates with a COUNTERCURRENT heat exchanger

Nota:

• the ability to maintain a constant internal environment in response to environmental changes

1. Feedback Loops

   Nota:

   • Positive Feedback Loops: a self-amplifying cycle where a physiological change leads to even greater change in the same direction Negative Feedback Loop: a process in which the body senses a change, and activates mechanisms to reverse that change
   1. Sensors
      1. Control Center (integrator, summator)
         1. Effectors
      2. Hypothalamus

         Nota:

         • Most important sensor found in mammals (thermostat) When the hypothalamus is cooled, metabolism increases and body temp increases When the hypothalamus is heated, metabolism decreases and body temp decreases
2. Regulating Temperature

   Nota:

   • 1. Insulation 2. Circulatory rerouting 3. Evaporative cooling *** dH/dt= C(TA-TB) C= conductance (TA-TB)= driving force
   1. Heat Production

      Nota:

      • 1. metabolism of nutrients (50% efficiency 2.muscle activity 3.shivering thermogenesis 4.non-shivering thermogensis (Brown Fat)
      1. Brown Fat

         Nota:

         • In brown fat the inner mitochondrial membrane is made leaky to H+ so energy is not used  to make a ATP but rather is released as heat
      2. Countercurrent Exchange
   2. Evaporative Cooling

      Nota:

      • -sweating -respiratory surfaces ( i.e. panting) -gular flutter (avians)
      1. Gular Flutter

         Nota:

         • Form of evaporative cooling used by avians Disadvantage: Loss of water

Nota:

• animals (mammals and birds) whose body temp varies at different times *Conserves energy by lowering body T set point

1. Torpor

   Nota:

   • Period of time when body temperature changes (hibernation) Ex; squirrels, bears, bats *Only one bird- hummingbirds

Nota:

• Q=DA((P1-P2)/L) Q= rate of diffusion D= diffusion coefficient A= surface area for exchange P1-P2= pressure difference L= diffusion distance

Nota:

• Ex: flatworms and insects insects take in air to the tissues via tracheae (air ducts), vunerable to dehydration

Nota:

• Terrestrial vertebrates breathe using internal lungs a circulatory system for transport (not very efficient) TIDAL VENTILATION (2 Way)

1. Surface tension

   Nota:

   • Causes the lungs the lungs to expand Collapsed lungs are a result of loss of surface tension
   1. Surfactant (detergent)

      Nota:

      • Substance produced by the lungs of humans  Important for preventing collapse of alveoli 
2. Anatomical Dead Space/ Residual Volume

   Nota:

   • Dead Volume: large amount of air in bronchi never reach the lungs Residual Volume: not all air is removed from lungs when exhaling (fresh air diluted by stale air)
3. Atmosphere Air/ Air in Lungs

   Nota:

   • Atmosphere: 21% O2, .03% CO2, 78% N2 Po2 in lungs= 114 mmHg (15%)

Nota:

• subunits of protein (globin) + heme (iron ring)

1. Hemoglobin (4)

   Nota:

   • Can bind to 4 molecules
2. Myoglobin (1)
3. Cooperativity vs Affintity

   Nota:

   • Cooperativity- sigmoidal shape of hemoglobin's oxygen-dissociation curve results from cooperative binding  Affinity- how easily the oxygen molecules bind to the molecule Fetus- needs stronger affinity for O2 to go thru the placenta Oxygen is not very soluble in blood plasma

1. Medulla (respiratory control center)

   Nota:

   • more soluble than O2 in solution (5%) bound as Hb (20%) as bicarbonate ions (70%) buffers plasma
   1. CO2

      Nota:

      • converted to HCO3- & H+

Nota:

• more soluble than O2 in solution (5%) bound to Hb (20%) ss bicarbonate ions (70%) *buffers plasma

Nota:

• Avians have both air sacs and lungs (sacs act as bellows)

1. Accessory sacs

   Nota:

   • Air sacs that at as bellows pushing air thru in one direction, and not for gas exhange surfaces

Nota:

• Problems: 1. Less air content in water 2. Oxygen diffuses thru water slower than air 3.Viscosity/ density of water

1. Countercurrent Exchange (One Way)

   Nota:

   • Gills have lamellae structures allowing for countercurrent exchange
2. One-Way Flow

   Nota:

   • freshwater moves continuously thru the gills during inhalation and exhalation

Nota:

• Capillaries are permeable to CO2, H2O, small proteins, and O2, but not large molecules such as large proteins and blood cells Blood cells flow single filePermeability regulated by pH, temp, and histamine

1. Osmotic Pressure/ Hydrostatic Presssure

   Nota:

   • net movement of fluid IN and OUT of the capillaries is determined by osmotic pressure (roughly the same) and hydrostatic pressure
2. Precapillary Sphinctors

   Nota:

   • Location of capillary exchange processes (found in capillary beds) 1. diffusion 2.bulk flow--osmotic pressure (inward)--blood pressure (outward)
   1. Influence of pH/ Temp

      Nota:

      • pH and temperature influence blood flow decreased pH opes capillary vents decreased temp constricts capilary

Nota:

• Vasculature Effectors: -Local factors -Autonomic N.S. -Hormonal

1. Autonomic Nervous System

   Nota:

   • Sympathetic & Parasympathetic Fight or Flight (Sympathetic)

Nota:

• As blood flows thru capillaries heat, O2, and waste are exchanged/ blood pressure drops

1. Peristalsis

   Nota:

   • Present in many invertebrates Muscular, and can contract and prevent blood flow from moving backwards
2. Chambered Heart Valves

   Nota:

   • Present in vertebrates Valves prevent blood flow from going backwards
3. Skeletal muscles & valves

   Nota:

   • Present in vertebrate veins Venous system in which blood moves thru veins using gravity or muscular contraction

Nota:

• Advantages: control volume and blood pressure seperately -different velocity -different pressure

1. Blood Pressure

   Nota:

   • Cardiac Output x Total Resistance Pressure pushes fluid thru the body, therefore low pressure would leave fluid in the lungs Blood Pressure= CO x Peripheral Resistance
2. Cardiac Output

   Nota:

   • How much blood is being pumped in a given time Heart Rate & Stroke Volume (HR x SV)

Nota:

• Takes in H2O w/ ions Removes urine and eliminates wastes (thru sweating/ respiratory evaporation)

1. Function: Bulk Filtration and Selective Reabsorption

   Nota:

   • 1. Filters the blood 2. Maintains plasma osmolarity & ions3. Eliminates waste
   1. Waste Elimination

      Nota:

      • nitrogenous waste- proteins, nucleic acids, nutrients ammonia (NH4OH)- toxic, highly solubleuric acid (C5H4N4O5)- not toxic, insolubleurea (CO(NH2)2)-non toxic, soluble*primary waste for humans
   2. Filtration

      Nota:

      • -happens at the glomerulus -large volume of plasma goes thru the the capillaries
      1. Movement

         Nota:

         • Blood pressure and osmotic pressure move water Urine produced can be more concentrated than blood
   3. Selective Reuptake

      Nota:

      • -happens in the proximal convoluted tubule -active transport  -reuptake of ions, water, and glucose
      1. Active Transport

         Nota:

         • 1. Movement of molecules against concentration gradient 2. Requires ATP (energy) 3. Specific protein transporter (none for water)
2. Nephron (subunit)

Nota:

• birds, fish, lizards all have other osmoregulators