Chapter 40 lecture Notes

anatomy

study of organisms physical structure

physiology

study of how physical structures within organisms function

What are the five characteristics that physical laws constrain?

* strength
* diffusion
* movement
* heat exchange
* size

What are the two distinguishing features of evolutionary convergence?

* reflects different species adaptations to similar environmental changes
* size/shape/composition: correlate to function

What are the two distinguishing factors of exchange across the cell membrane?

* rate proportional to cell surface area
* amount proportional to cell volume

What are the correlations between form and function for exchange across the cell membrane?

* start at molecular level (protein shape)
* also true at cell level (secretory cell show much rough ER and golgi)
* cell shape and function correlated (absorptive cells: large surface area)

Why is surface area important?

For gas exchange and absorption

* higher surface area means more likely to get nutrients through absorpotion

What is the difference between flat vs. complex bodies?

Flat animals have minimal distance between their cells and the environment whilst complex organisms have highly folded internal surfaces for material exchange

Do internal folds create more or less surface area?

More

What are the two main jobs of interstitial fluids in vertebrates?

* maintains stable fluid internal environment
* allows for ease of movement into and out of cells

What is the hierarchical arrangement of systems within mammals?

specialized cells → tissues → organs → organ systems

What is an example of an organ that is in more than one system? What are the systems?

pancreas is in both the endocrine and digestive system

Gland

cell group secreting specific molecules or solutions

Why is it so difficult to grow skin and organs?

Each tissue requires different environments to grow in. (PH, fluid, etc.)

What are the two main characteristics of tissues?

* group of similar cells functioning as a unit
* structure correlates to function

What are the four types of tissues?

1. epithelial
2. connective
3. muscle
4. nervous

What do epithelial cells do?

* cover body exterior
* line organ surfaces
* cells closely joined
* form glands
* provide protection

What three things do the epithelial cells regulate?

* heat transfer
* water transfer
* nutrient transfer

What are the three types of epithelial cell layering and how many layers do they have?

* simple (1)
* stratified (8-10)
* pseudostratified (1 but appears to have more)

Examples of epithelial tissue?

skin, oral cavity, lungs etc.

What is connective tissue?

cells loosely arranges in liquid or jelly-like or solid extracellular matric

What secretes the matrix in connective tissue and how is it bounded?

* by cells
* bound by collagens and elastic or reticular fibers

What are the two cell types within connective tissue?

* fibroblasts/macrophages

What are the four categories of connective tissues?

1. loose connective
2. Fibrous or dense
3. supporting (bone, cartilage)
4. fluid (blood)

Which type of tissue is the most diverse?

connective

What does loose connective tissue do? Give an example

Packing material between organs or padding beneath skin

* adipose

What are the two types of connective tissues?

What do they contain?

Tendons and ligaments

* contains many tough collagen fibers

What is supportive connective tissue?

Give two examples?

Firm extracellular matrix

* bone
* cartilage

What is fluid connective tissue?

Give an example

Consists of cells surrounded by liquid extracellular matrix

* blood

What is the extracellular matrix made by in fluid connective tissue?

plasma

What are the three types of muscle tissue?

1. Skeletal Muscle
2. Cardiac Muscle
3. Smooth Muscle

Skeletal Muscle:

* what does it do? (3)
* voluntary or involuntary?

1. exerts force on bones
2. encircles openings of digestive and urinary tracts (sphincters)
3. makes up most of vertebrate body muscle

(voluntary)

Cardiac Muscle:

* What does it do? (3)
* how is it unique?
* voluntary or involuntary?

1. makes up heart wall
2. physically and electrically connected to each other
3. transmit heartbeat signals

* unique because of branching

(involuntary)

Smooth muscle:

* What does it do?
* involuntary or voluntary?

* Lines walls of digestive tract and blood vessels/has tapered ends
* involuntary

Which type of muscle has cells that are multi-nucleic?

skeletal muscles

Which muscle types are striated? Which aren’t?

striated = cardiac and skeletal

non-striated = smooth

What are the two cells that make-up nervous tissue?

* neurons
* glial cells

What is the purpose of glial cells?

To support neurons

Neurons:

* What do they do?
* size/shape?
* cell projections?

* transmit impulses
* vary in shape and type
* dendrites (receiver)/axons (senders)

Homeostasis

maintenance of relatively constant internal environment, despite varying environmental change

What are the two processes that allow of constancy of physiological state?

* conformation
* regulation

Conformations

vary internal condition with certain external changes

regulation

moderate internal change via internal control mechanisms despite external environmental fluctuation

What are the two ways that homeostasis is achieved?

* monitoring internal conditions
* adjusting rapidly to changes

What are the three general components of maintaining homeostasis and what do they do?

1. integrator → evaluates and decides response
2. Effector (restores)
3. Sensor (detects change)

What are the two types of homeostasis feedback?

1. Negative feed back (opposes → common)
2. Positive feed back (enhances → rarer)

Give an example of negative feedback

You are super hot from working out so your body starts to create sweat, allowing water to evaporate

Give an example of positive feedback

increase in oxytocin post birth

Set points

normal ranges of vitals

What is cyclic variation?

Your bodies set points will change with age

What two things does the rate of diffusion across membranes partially depend on?

* amount of surface area available for diffusion
* cell volume

As cells get larger, volume (blank) much (blank) than surface area

increases;faster

What are three ways in which structural shape increases surface area relative to volume? Give an example of each

1. flattening

fish gills: flattened sheet-like structures or lamellae


2. folding

mammal small intestine has folds or villi


3. Branching

small blood vessels (capillaries): highly branched

Thermoregulation

process for maintaining internal temperature within tolerable ranges

What are the three main aspects of endothermy in endothermic animals?

Example of those animals?

* Generate heat by metabolism
* active at greater temperature range
* costly

(birds/mammals)

What are the two main aspects of ectothermic animals?

Example of those animals?

* gain heat from external environment
* tolerate greater ranges

(invertebrates/fishes/amphibians)

hemeotherms

keep body temperature constant

What are the three main characteristics of heterotherms?

* tolerate changes in body temp
* body temp varies with environment
* relationship between heat source and body temp is not fixed

Give an example of an animal with a small body temp range and an example of an animal with a large body temp range

humans = small range

bats = large range

Why are fish considered ectoterms and homoterms?

Because their body temperature changes with the water temp

Overheating causes…

causes protein denaturation → cease function/leads to dehydration

very low body temp causes…

slow down enzyme function → energy production

What are the four way animals exchange heat with the environment?

1. conduction
2. convection
3. radiation
4. evaporation

Conduction

direct heat transfer between objects in contact

convection

heat exchanges between solid versus gas or liquid flow

radiation

heat transfer between objects not in direct physical contact (sunbathing)

evaporation

Phase exchange: liquid to gas

Is water or air a better conductor of heat?

water is a much better conductor

What is the benefit of air being a poor heat conductor?

because air is a poor heat conductor, it is a good insulator so it accounts for elaborate external insulatory structures trapping air/slowing heat loss

What are the five thermoregulatory adaptations?

1. insulation
2. circulatory adaptations
3. cooling by evaporative heat loss
4. behavioral responses
5. adjusting metabolic heat production

What is insulation?

Example?

Major thermoregulatory adaptation for mammals and birds

\*blubber: special types of fat for insulation against cold seawater

What is the purpose of fat on humans?

NOT FOR INSULATION! For organ protection

Why do small mammals have high metabolisms?

Because they have a large surface area to volume ration which allows for rapid heat loss

Why are babies born with a lot of brown fat?

Because it helps them maintain body temp

Circulatory adaptation (thermoregulation):

Who uses it?

altering blood flow near body surface affects thermoregulation

* used by endotherms and ectotherms

What is vasodilation and what does it facilitate?

Blood flow to skin increases

* facilitates heat loss/gain

What is vasoconstriction and what does it facilitate?

Blood flow to skin decreases

* lowers heat loss/gain

Give an example of when vasodilation occurs and why?

When you are working out and your skin becomes pink because your muscles warm up

Give an example of vasoconstriction

you have pale skin when you are cold because the blood is kept towards the center of the body to conserve warmth

countercurrent exchange

transfer heat/gases/solutes between fluids flowing in opposite directions and reduce loss

countercurrent multipliers

small differentials along exchanger sum to create large differental from start to finish

Where can you find heat conserving vascular systems in some animals?

* in flippers
* in legs
* some insect thoraxes
* some body fish and sharks

What is an example of a behavioral response to control body temp?

dragonflies change their posture to minimize the body surface that is exposed to the sun

thermogenesis

example?

adjustment of metabolic heat production to maintain body temp

increase via muscle activity (moving/shivering)

non-shivering thermogenesis

Example?

when hormones cause mitochondria to increase metabolic activity

* brown fat use

is shivering considered negative or positive feedback?

Negative

What are some examples of variable seasonal insulation changes?

Used by birds and mammals (hair thickening or loss/feather molting)

What do arctic fish produce that prevents ice formation in the cells?

Antifreeze

Which part of the brain interprets the neuronal signals in regards to temperature?

hypothalamus

Bioenergetics

overall flow and transformation of energy in animals

When needs for staying alive are met, what are the three ways remaining food molecules can be used?

1. Biosynthesis (body growth and repair)
2. Synthesis of storage material (fat)
3. Gamete production

Metabolic rate

overall rate of energy consumption by animal

Basal metabolic rate

rate that ENDOTHERMIC animals consume oxygen at rest/with an empty stomach/under normal comfortable temperature and moisture conditions

Standar metabolic rate

metabolic rate of ectotherm measured at rest at specific temperature

At comparable sizes, do ectotherms or endotherms have lower metabolic rates?

ectotherms have much lower metabolic rates

At what ages does you metabolic rate increase?

At what ages does it stay constant?

* increases from 0-20 years old
* stays the same from 20-60 years old

Do small or large animals have higher BMR/SMRs?

Give an example to explain why this is

* small animals

For instance, elephants have more mass than mice but one gram of an elephants tissue consumes less energy than one gram of a mouses tissues

What has to happen to mass specific metabolic rate when an organisms size increases? Why?

MSM must decrease

* this is because surface area available for exchange of materials would fail to keep up with metabolic demands of animal if it didn’t

Do larger animals have a faster or slower heart rate than smaller animals?

slower

Torpor

physiological state where activity is low and metabolism decreases