exam 3 pwrpt 1

• nervous
• endocrine
• muscle
• skeletal
• reproductive
• digestive
• respiratory
• cardiovascular
• excretory
• lymphatic
• immune
• skin

• epithelial
• connective
• muscle
• nerveous

• sheets of densley packed and tightly connected cells that cover inner and outer body surfaces
• some epithelial tissues have specialized functions: secretion, cilia, taste, smell, protective, absorptive, transport, boundaries

• made of elongated cells capable of contracting and causing movement by sliding of protein filaments past each other
• most abundant tissues in the body
• three types: skeletal, cardiac, smooth

responsible for locomotion and other body movements (e.g. breathing, shivering

makes up the heart and is responsible for the heartbeat and blood flow

involved in movement and generation of forces in internal organs (e.g. gut, blood vessels)

comosed of neurons and glial cells

• extremely diverse in size and form
• function by generating electrochemical signals in the form of nerve impulses, these impulses are conducted via long extensions to other parts of the body where they communicate (often via chemicals realesed at synapses) with other neurons, muscle cells, or secretory cells to contral activities of organ systems

provide a number of support functions for neurons

• consists of cells embedded in an extracellular matrix that they secrete
• an important component of the extracellular matrix is protein fibers (e.g. collagen, elastin, cartilage)

• most common protein fiber in connective tissue matrix
• very strong fiber
• very dense in tough tendons and ligaments
• forms netlike framework for organs to give shape and strength
• it has low density as loose strands whin it fills in between organs

• protein fibers that can be stretched to several times its resting length and then recoil
• tissues that are regularly stretched, such as lung walls and artery walls have abundant elastin

a network of collagen fibers embedded in a flexible matrix of proteins and carbs, chondrocytes secrete matrix

hardened by the deposition of calcium phosphate

• a connective tissue that forms and stores droplets of lipids
• adipose tissue serves as a fuel reserve and as a cushion to protect internal organs. Layers of adipose tissue under the skin help insulate against heat loss

• a connective tissue made up of cells in a fluid extracellular matrix called blood plasma
• plasma also contains an abundance of proteins

a discrete structure that carries out a specific function in the body

a group of organs that function together

• temp
• gas content
• humidity
• water
• mineral availability
• light
• etc.

• temp
• gas content
• salinity
• pH
• hydrostatic pressure
• light
• etc.

spp. that are extremely tolerant of a wide range for a particular parameter

spp. that are not very tolerant of range of a particular parameter

species that match their internal environment (as regards to a particular parameter) to the external conditions

species that control their internal environment to a particular set-point for a given parameter even though the external environment varie

the maintenance of constant conditions in the internal environment of an organism

• extracellular fluid
• cells

signals any discrepancy between the set point and the conditions present

the particular desired conditoin level

the difference between the set point and the feedback information

control center compares magnitude of variable to the set point value, integrates the information, and controls the response of the effector system(s) which control the magnitude of the variables bringing it back to set-point

• cells, tissues and organs that respon to commans from regulatory systems
• called controlled systems

obtain, process, and integrate information, then issue commands to controlled systems, which effect change

imformation that couses a regulatory system to reduce or reverse a process

information that tells a regulatory system to amplify a response

information signals the system to change the setpoint. May anticipate change

temperature

high temp makes processes go faster (as long as T isn't high enough to kill the organism)

• the rate of reaction at a particular temperature (R_T) divided by the rate of the reaction at a temperature 10ºC lower (R_T-10)
• most biological Q10 values are between 2 and 3

a biochemical adjustment of enzyme systems to counter the effects of temperature

natural adaption, ex. metabolic compensation

maintain a constant body temperature, freeing them from Q₁₀ effects

body temperature changes when environmental temperature changes

animals that regulate body temperature at a constant leve some of the time

hibernating animals

keep core T constant but allow the periphery to vary if necessary (most homeotherms)

(most animals aside from mammals and birds) depend on external heat sources to maintain body temperature

(all mammals and birds) regulate body temp by (1) generating metabolic heat and (2) preventing (controling) heat loss

• ectotherms: metabolism decreases as air temperature decreases
• endotherm: metabolic rate increases as temperature decreases

Heat Loss = Heat gain

conduction convection, radiation, evaporation

conduction, convection, radiation, metabolism

• takes place between two solids in contact with one another. Direct transfer of the kinetic energy of molecular motion
• Rate depends on: temp gradient between the two (T1-T2); surface area in contact (A); coefficient of thermal conductivity (K, expression for the ease of heat flow in a material)

Rate = KA(T1-T2)

• takes place between a solid and a fluid, or between two fluids
• factors are same as conduction (K, T gradient, A)
• K is greater for water than for air

• any object above absolute zero loses heat via radiation
• the intensity varies directly with the temperature of the radiating surface
• the wavelength varies inversely with surface T
• objects at physiological T's emit mostly in the middle and long infared
• skin color doesnt matter much for the radiating surface but does matter for how much solar radiation is absorbed

• metabolic rate
• evaporation
• insulation (conduction, convection, radiation)
• vascular control (conduction, convection, radiation)
• behavior (postural changes, burows, huddling, choice of microhabitat)

• metabolism
• evaporation
• some behaviors

• insulation
• vascular changes
• some behaviors

• thermal neutral zone
• within this zone the animal uses non-energetically costly meant to control TB

• lower critical temperature
• animal must increase metabolism to generate more heat

• upper critical temperature
• the animal must use evaporative cooling to maintain TB constant

• decrease conductive, convective and radiation heat loss: insulation, blood flow, behavior, body shape
• decrease evaporative heat loss
• increase metabolic rate

• evolutionary
• seasonal
• immediate

• all time scales
• fur, feathers, blubber
• fur and feathers trap air (lo "K")
• insulation lowers conductive, convective and radiative heat loss
• better insulation lowers the LCT and decreases the slope of the MR vs TA line

• peripheral vasoconstriction and dilation
• heat exchangers
• heat sinks (thermal windows)

blood flow to limbs is periodically opened and closed to control heat loss, but not allow hand T to drop too far

veins run next to arteries so that the blood going to the core is not as cold and not as much heat is lost to the environment

lots of blood vessels near the skin

• postural (decrease SA/ Volume)
• huddling
• microhabitat selection: out of wind, sunny slope, burrow, subnivean (under snow)
• burrowing in snow

• increase activity
• shivering
• non-shivering thermogenesis: brown adipose tissue, other (thyroid hormone, etc.)

• sole function is heat production
• brown fat is commonly found in newborns, animals that hibernate, and many active mammals in winter
• brown fat cells have the protein thermogenin

protein which uncouples proton movement from ATP production, so that no ATP produced, but heat is released

• increase heat loss via conduction, convection and radiation: insulation changes, vascular, behavioral
• metabolic rate
• evaporative water loss
• heat storage

• the major adaptation to hi TA and/or TB
• problems: costs energy, water loss, loss of effectiveness at high humidity
• sweating, panting

• temporary increase in body T
• heat exchangers cool blood perfusing the brain
• found in numerous species especially those capable of long term running, not present in cheetah

• some ectotherms can use behavior to regulate body temperature in the natural environment
• behaviors include basking in the sun, seeking shade, burrowing, or orienting the body with respect to the sun
• endotherms also use behavioral thermoregulation. Most animals select the best thermal environment whenever possible, for example by seeking shade, breezes, etc.

color change: darker to increase radiation gain, lighter to decrease radiation gain

• increased swimming power and speed
• faster digestion and absorption (permits smaller stomach, more muscle mass per body volume)
• retina, visual predator
• brain, faster neural processing
• allows range expansion to cooler waters

• the vertebrate thermostat
• the temp of the hypothalamus itself is the major source of feedback information in many species
• negative feedback system

• a rise in body temperature in response to pyrogens, they cause a rise in the hypothalmic set point.
• immune system cells called macrophages attack pyrogens and release interleukins, chemicals that signal other cells and trigger other responses, including release of protaglandins

come from foreign substances such as invading bacteria or viruses

produced by cells of the immune system

raise hypothalamic set point

• animals can save energy by turning down the thermostat below normal
• many animals use regulated hypothermia as a means of surviving periods of cold and food scarcity

regulated hypothermia lasting days or weeks with drops with drops to very low temperatures

adaptive hypothermia that can drop body temp 10-20ºC and save considerable metabolic energy (hummingbirds)