Exam 1 Study Guide

What is comparative physiology?

Bio 303 – General Physiology

Physiology is the science of functions

- It focuses on identifying the casual contribution of a part to the whole  organism

- We can compare different organs & organ systems

Comparative physiology is the comparing and contrasting of physiological  mechanisms, processes, or responses across a species, or within one, under  different conditions

Making of a model. Ideal circumstances

- Rapid evolution  short life, rapid cycle

- Many differences  phenotypes

- Having a history an understood evolutionary back story

- Convergence  different species within the same trait

- A good pedigree  rapid development, sexual maturity, small adult size, easy  availability & the ability to track and alter genes.

Homeostasis- maintenance of a constant internal environment

What are the challenges for multicellularity?

-survival is the immediate goal

Selective pressures for multicellularity

- Aquatic organisms 

o Adherence to substrate

o Prevent being eaten

o Faster movement

 Specialization in locomotion (fins on fish)

- Terrestrial organisms 

o More effective spore/ germ cell dispersal

o Better feeding

o Mobile  can move or hunt

 Gets the resources that are needed

Challenges for multicellularity

- Large size  long diffusion distance  

o Vascular system built for transport

- Subdivision of organismal functions  tissues & organs

Unicellular

- Intracellular spaces

- Intraorganellar spaces

Multicellular

- Intraorganellar space

- Intracellular space  has fluid

- “interior” extra cellular space

o Interstitial space

What are 4 types of animal histological tissues?

o Intravascular space

- Exterior space

-

o All of these spaces are regulated.

 All membranes and epithelial tissues are barriers & separate  spaces from each other

 -proteins are well anchored, while enzymes are not.

o at low temps, the membrane may become like a gel or stiff If you want to learn more check out  Why did you buy it?

 if things cannot interact, nerves wont transmit

∙ animals and plants can control the fluidity of the  

membrane

- epithelial cells- joined to one another by tight junctions (can be “leaky”) o can be organized into sheets or tubules

- function of membrane proteins 

o transporting materials into the cell

o binding to other cells

o receiving signals from the environment

o acting as enzymes in chemical reactions

- the lipid bilayer effectively separates 2 aqueous components o lipophilic- (hydrophobic) molecules are permeable across the lipid  bilayer in proportion to their lipophilicity

o hydrophilic molecules can achieve transmembrane passage by way of  protienacious channels and pores

- simple diffusion 

o molecules in a solution above absolute temp are in motion

o the velocity of movement is proportional to temperature

- tissues 

o groups of similar cells

- organs 

o internal structures that carry out specific functions

 usually composed of all 4 types of tissues

- the internal environment is the extracellular fluid that serves all the  needs of the cells of the body

- organisms must maintain their internal environment in a state of  homeostasis – a narrow range of stable and optimal physical &  biochemical conditions

- negative feedback

o info used to counteract the influence that created the error signal - positive feedback- used to amplify a response

o example – sexual behavior

- small changes in temp can have large physiological effects - animals can be classified by their thermoregulatory characteristics - homeotherms 

o animals that maintain a constant body tempDon't forget about the age old question of • What are the 5 characteristics of North Africa and Southwest Asia?

- poikicotherms 

o animals that fluctuate in body temp

- endotherms 

o birds and mammals that have the ability to vary their metabolic heat  production to compensate for the loss of heat to the environment - ectotherms 

o invertebrates, fish, amphibians, are largely dependent on the  environmental sources for heat

- heterotherms 

o organisms that act like endotherms and ectotherms

- energy budgets reflect adaptations for regulating the body temperature o radiation

o convection

o conduction

o evaporation

- countercurrent heat exchange 

o the adaptation of heat being exchanges between blood vessels  carrying blood in opposite directions

- brown fat is tissue specialized in nonshivering heat production - hypothermia- below body temp

-

- Simple diffusion across the membrane  

o colligative properties

 vapor pressure reduction

 boiling point elevation

 freezing point depression

 osmotic pressure

- facilitated diffusion 

o no energy required

o “downhill”

 Movement is driven by concentration gradient We also discuss several other topics like Core issue: how much?

- Active transport 

o Energy is required

o Up hill

o Primary or secondary transport

 Movement is driven against concentration gradient

- Uniporter 

o One substance in one direction

- Symporter 

o Two different substances in the same directions

- Antiporter 

o Two different substances going in different directions

- Turgor pressure pushes a plant cell membrane against the cell wall  in a hypotonic solution

- Primary active transport

- Secondary active transport

- Passive ion transport  

o Driven by concentration (chemical) and electrical gradients - Electrical charge difference is important in determining movement

- There are 4 types of animal histological tissues Don't forget about the age old question of What does it mean to be a manager?

o Neural

o Connective

o Epithelial

o Muscle

- Sensors 

o These cells of the retina encode info about the externa environment - Neurons 

o Communicate information from sensors to the central nervous system  (CNS). Stores, integrates info & communicates commands to the  muscles and glands

- Glia 

o Support neurons in many ways – modulate their signaling; insulate  neuronal processes, provide immune functions for the CNS

- Dendrites 

o Receive info from other neurons

- The cell body contains the nucleus and most cell organelles - Info collected by dendrites is integrated in the axon hillock which generates  action potentials

- Axon 

o Conducts action potentials away from the cell body

- Axon terminals synapse with target cells We also discuss several other topics like Why is it good to have?
Don't forget about the age old question of Where is the DNA located?

- Varieties of neurons

o Sensory

o Motor

o Interneuron

- The membrane potential

o Ionic asymmetries of cations and anions and electrically charges  molecules across a biological membrane

 There are some molecules with charges, but never leave the cell - Macroscopic eletroneutrality 

o When the number of positive and negative charges equal each other  Can be on the inside or outside of the cell

- Most animal cells have a resting membrane potential of -70Mv - Resting membrane potential is generated by ion channels supported by  pumps

o Leak K+ channels generate resting pot.

o Increased Na+ permeability depolarizes (less neg.) the membrane o Increased K+ permeability hyperpolarizes the membrane (more neg.) - The lipid bilayer isn’t perfect; it may have some “leaky” spots that ions can  sneak through

o Ex- tails

- Opening Na+ channels  makes the inside more positive as it enters - The change in potential depends on how many ions enter - The action potential

o Initiated when the membrane potential achieves threshold. Prior to  achieving this, the membrane reflects passive electronic effects on  membrane conductance’s

- Activation gate opens quickly

- Inactivation gate closes slowly 

o K+ channel doesn’t have an inactivation gate

 This process happens very quickly. About 2-3 MS

- After the peak of an action potential

o Many Na+ ion channels begin to close and many K+ channels begin to  open

- Electrical synapse 

o Rapid cell to cell transfer

- Chemical synapse 

o Slower cell to cell transfer

- Excitatory synapse 

o Neurotransmitter stimulates generation of action potential - Inhibitory synapse 

o Maintains the post synaptic membrane potential at a value more  negative than threshold

- Withdrawal reflex  reporting function

o Ex.

 Something is hot, you pull away

 Withdrawal of one leg, your body needs to prepare for the new  weight distribution

- Sensory physiology

o Receptor cells express transducer function

- 2 classes of receptors

o Direct 

 Sensory receptor is a neuron

o Indirect 

 Sensory receptor synapses with a neuron

- Excitation

o +

 Depolarization

- Inhibition

o –

 Repolarization

- Hair cells 

o Possess processes that transmit small mechanical stimuli to  mechanosensitive channels that, in turn, transduce a mechanical  disturbance into a coded electrical signal

- Ear is composed of 3 parts

o External

 Pina

o Inner

 Cochlea

∙ coiled in mammals

 vibrations are detected by receptor hair cells in the Scala media  of the cochlea

o middle

 tympanic membrane

∙ function as an impedance matching device to effectively  

convert sound waves in air

- time delay 

o we compare arrival times of sound between 2 ears

- differential intensity 

o ear closer to sound will receive stronger stimulus

 louder

- sensory adaptation is the process through which the response of a  sensory system is reduced through continuous stimulation - there are 2 categories of photoreceptors

o ciliary photoreceptor 

 the photo pigment is located in the folded membrane of a  modifies cilium

o rhabdomeric photoreceptor 

 the photo pigment is located in the membrane of apical  microvilli

- camera eye 

o light is received through a single opening

- compound eye 

o light is received through multiple openings

- single ommatidium 

o composed of 8 retinula cells

- rod 

o stacked membrane disks

 extremely large surface area

- Rhodopsin 

o Opsin (protein) 

+ 

o Retinal (cofactor) 

- Rods

o Gray scale

o Dim light

o High convergence

o 1 visual pigment

- Cones

o Color

o Bright light

o Low convergence

o 4 visual pigments

 R, G, B, UV