Chapter 40Basic Principles of Animal

Form and Function

AP Bio- 1/2

Overview: Diverse Forms, Common Challenges

Anatomy is the study of the structure of an organism

Physiology is the study of the functions an organism performs

Form and function are related

An animal’s size and shape (body plan or design) affect the way it interacts with its environment.

Hierarchal Organization of Body Plans

Emergent properties(AP Bio Review Ch.1) Most animals are made up of groups of cells

that are organized into tissues that have different functions according to their structure. › Epithelial › Connective› Muscle› Nervous

Tissues make up organs, which all together make up organ systems.

Organ System and Organs

Tissues

CellEmergent properties are due to the arrangement and interactions of parts as complexity increases.

Epithelial Tissue

Covers the outside of the body and lines the organs and cavities within the body

Closely joined cells: barrier against mechanical injuries, pathogens, and fluid loss

Shape of Epithelial:› Cubodial (like Dice)› Columnar (like Bricks)› Squamous (floor tiles)

Arrangement of epithelial cells: Simple (single cell layer), Stratified (multiple layers of cells) pseudostratified (a single layer of cells of

varying length) Different cell shapes and arrangements have distinct functions.

Connective Tissue

Connective tissue mainly binds and supports other tissues

Has sparsely packed cells scattered throughout an extracellular matrix

The matrix consists of fibers in a liquid, jellylike, or solid foundation

Three types of connective tissue:› Collagenous fibers: provide

strength and flexibility› Elastic Fibers: stretch and snap

back to their original length

› Reticular Fibers: Join the connective tissue to adjacent tissue

Connective tissue contains cells: › Fibroblasts: that secrete the

protein of extracellular fibers

› Macrophages: involved in the immune system

Shows the macrophages and the collagen and the interstitial fluid that fills the spaces between the cells.

Six major types of connective tissue: › Loose connective

tissue: binds epithelia to underlying tissues and holds organs in place

› Cartilage: is a strong and flexible support material

› Fibrous connective tissue: is found in tendons, which attach

muscles to bones, and ligaments, which connect bones at joints

› Adipose Tissue: fat for insulation and fuel

› Blood Tissue: composed of blood cells and ell fragments in blood plasma

› Bone Tissue: mineralized and forms the skeleton

Connective Tissue cont.

The variation of the matrix results in six different types of connective tissue

Muscle Tissue

Muscle tissue consists of long cells called muscle fibers, which contract in response to nerve signals

Three types in the vertebrae body

› Skeletal muscle: or striated muscle, is responsible for voluntary movement

› Smooth muscle: responsible for involuntary body

activities

› Cardiac muscle: responsible for the contraction of the heart

The cells in each muscle tissue responsible for all types of body movements.

Nervous Tissue Nervous tissue senses

stimuli and transmits signals throughout the animal

Nervous tissue contains:› Neurons, or nerve

cells, that transmit nerve impulses

› Glial cells, or glia, that help nourish, insulate, and replenish neuronshttps://www.youtube.com/watch?v=y2N_b0qwvxY

Neuron

Glial

DendriteCell body

Axon

An example of a neuron.

Comprehension Check

Write E for epithelial, M for muscle, C for connective, and N for nervous tissue

1. ____ Dice shaped cells2. ____ transmits signals3. ____sparse population of cells scattered through an EM4. ____loose connective tissue, adipose tissue, fibrous

connective tissue, cartilage, bone, and blood5. ____cardiac muscle, smooth muscle, skeletal muscle 6. ____consists of long cells called muscle fibers7. ____ closely joined cells8. ____ consists of fibroblasts and macrophages9. ____ binds and supports other tissues10. ____contain glial cells

C

CE

M

M

CC

N

N

E

Endocrine System vs. Nervous Systems

Endocrine System› Transmits chemical signals called hormones

to receptive cells throughout the body through the bloodstream.

› A hormone may affect one or more locations throughout the body.

› Hormones are relatively slow acting, but can have long lasting effects.

› The endocrine system is well suited for coordinating gradual changes that affect the entire body including growth and development, reproduction, and metabolic processes.

Nervous System Neurons transmit information between

specific locations. The information transmitted depends

on a signal’s pathway, not the type of signal.

Each signal is called a nerve impulse which travels to a target cell along a dedicated communication line, consisting of the neuron extensions called axons.

Target cells: neurons, muscle cells, endocrine cells, and exocrine cells. It conveys information by the pathway the signal takes. Signaling in the nervous system involves more than one type of signal. Nerve impulses travel within axons and change in voltage. Passing signals from one neuron to another involves short range chemical signals.

Transmission is fast; they take only a fraction of a second to reach the target and last only a fraction of a second. Signaling in the endocrine

and nervous system

Regulators vs. Conformers Regulators: when an animal uses internal

control mechanisms to regulate internal change in the face of external fluctuation.› A river otter keeps its body at a temperature

independent of that of the water’s temperature. Conformer: when an animal allows its

internal condition to conform to external changes in the variable.-Largemouth bass conforms to the temperature of

the lake in which it lives. As the water warms or cools, the cells of the bass do as well.

An animal may regulate some internal conditions while allowing others to conform to the environment. Ex: › Even though the bass conforms to the

temperature of the surrounding water, the solute concentration in its blood and interstitial fluid differs from the solute concentration of the fresh water in which it lives. This is because the fish’s anatomy and physiology enables it to regulate internal changes in solute concentration.

The relationship between body and environmental temperatures in an aquatic temperature regulator and an aquatic temperature conformer.

Homeostasis Homeostasis is when animals maintain a relatively

constant internal environment even when the external environment changes significantly.

  History: Claude Bernard: made distinction between

external environments surrounding an animal and internal environment in which cells of the animal actually live. He recognized that many animals tend to maintain relatively constant conditions in their internal environment, even when the external environment changes. His “constant internal milieu” is incorporated into the concept of homeostasis, which means “steady state” or internal balance

Maintaining Homeostasis: Animals maintain homeostasis by maintaining a variable (i.e.: body temperature or solute concentration) at or near a set point. Fluctuations in the variable above or below the set point serve as the stimulus. A receptor, or sensor, detects the stimulus and triggers a response, a physiological activity that helps return the variable to the set point.

https://www.youtube.com/watch?v=_0afKWu4yVg (15 min)

An example of the body’s response to a fluctuation in temperature to keep constant.

Negative Feedback vs. Positive Feedback

Negative Feedback: a response that reduces the stimulus.› When you exercise, you produce heat, which

in turn increases body temperature. Your nervous system detects this increase and triggers sweating. The evaporation of moisture from your skin cools your body and helps return your body temperature to its set point.

Positive Feedback: it occurs in animals but does not usually contribute to homeostasis. It triggers mechanisms that amplify the stimulus. The baby signals contractions in the mother to begin childbirth, which is an example of positive feedback.

  Normal Range: When animals have an upper

and lower limit rather than a single set point which allows for additional fluctuation.

Acclimatization: process by which an animal

adjusts to changes in its external environment. (temporary change)

Nonliving example: Regulating room temperature depends on a control center that detects temperature change and activates mechanisms that reverse that change. (neg. feedback)

Comprehension CheckFill in (a) for endocrine system or (b) for nervous system.

__Coordinates immediate and rapid responses including quick locomotion__Releases hormones that effect cells that contain certain receptors for that individual hormone. __The signal, a nerve impulse, moves along communication lines called axons__Signals involve short range chemical signals__Transmission occurs within a fraction of a second__The effects are relatively long because the hormones remain in the bloodstream and tissue for seconds, minutes, and even hours __Coordinates growth, development, reproduction, and digestion__Target cells include neurons, muscle cells, endocrine cells, and exocrine cells

A

B

A

B

B

AAB

Thermoregulation Thermoregulation: the process of an animal maintaining an

internal temperature in a certain range.› The hypothalamus in the brain contains nerve cells that

function to regulate internal body temperature Endothermic organisms(birds/mammals) use heat generated

internally by metabolism for warmth› Often have a warmer internal body than the environment.

Ecothermic organisms: (reptiles/invertebrates) use heat from an external source for warmth https://

www.youtube.com/watch?v=TSUCdLkI474 ( 5 min)The

thermoregulation function of the hypothalamus in human thermoregulation

Vaso(dilation/constriction) During vasodilation, an organism

increases the diameter of blood vessels near the skin.› This results in an increase in blood

flow in the skin that gives off heat to the environment, cooling the body organism.

Vasoconstriction reduces the diameter of blood vessels to reduce the blood flow› This results in less heat leaving the

organism keeping the internal body warm.

Vasodilation vs. Vasoconstriction

Other Forms of Thermoregulation

A countercurrent heat exchanger is used to prevent heat from exiting an organism› This is done by

having multiple blood vessels be adjacent to each other which allows for a heat transfer from the warm vessels to the cold ones. This process can

be turned off in order to increase heat loss.

Ectotherms will seek a warm area when their body temperature is cold or a cold are when they are warm.

Thermogenesis is the production of heat and is used by endotherms to stay warm.› An example would

be shivering where organisms produce heat by additional body movement when cold.

These are concurrent exchangers who trap heat in the body. The heat in the arterial blood emerging from the body core is transferred directly to the returning venous blood.

Acclimation in Thermoregulation

Organisms change in order to regulate their body heat in response to changing environmental temperature.› Endotherms often accomplish this by

changing externally such as growing a coat of fur to stay warm in the winter and shedding it during the summer.

› Ectotherms often change at the cellular level Using variations of enzymes that function

at differing optimal temperatures. Changing the proportion of saturated and

unsaturated lipids due to the presence of unsaturated lipids keeping the membrane fluid in colder temperatures.

Some ectotherms are able to produce various ‘antifreeze’ compounds to prevent ice from forming in cells.

Comprehension Check

The maintaining of internal temperature inside an organism ____________

Organisms such as reptiles that obtain heat from the external environment _______

Organisms such as mammals that generate internal heat________

Narrowing blood vessels to decrease heat loss ________

Expanding blood vessels to increase heat loss________

The adjacent arrangement of arteries and veins to reduce heat loss in an organism __________________

Thermoregulation Endotherms Concurrent Heat ExchangeVasoconstriction Vasodilation Ecthotherms

Thermoregulation

Ecthotherms

EndothermsVasoconstrictionVasodilation

Concurrent Heat Exchange

Bioenergetics The overall flow and

transformation of energy in an animal.

Metabolic Rate- The amount of energy an animal uses in a unit of time.

Influenced by age, sex, size, activity, temperature, and nutrition.

Endotherms use far more energy than ectotherms due to metabolism.

https://www.youtube.com/watch?v=nDCxIpiI7-Y (10 min) Overview of Bioenergetics in an animal.

Metabolic Rate Metabolic rate is roughly

proportional to proportional to the body mass to the ¾ power.(m3/4)

Basal Metabolic Rate (BMR)- The minimum metabolic rate of a nongrowing endotherm that is at rest, has an empty stomach, and is not experiencing stress.

Measured under a “comfortable” temperature range for the endotherm.

The relationship of metabolic rate to body size.

Metabolic rate Standard Metabolic rate- The metabolic

rate of a fasting, nonstressed ectotherm at rest at a particular temperature.

Torpor- A physiological state in which activity is low and metabolism decreases.

Enables animals to save energy while avoiding dangerous or harsh conditions.

Energy budgets for four animals. (annual energy expenditures)

Types of Torpor Hibernation- long-

term torpor that is an adaptation to winter cold and food scarcity.

Estivation- Summer torpor that allows animals to survive long periods of high temperatures and scarce water.

Body temperature and metabolism during hibernation in Belding’s ground squirrels.

Daily Torpor All endotherms that use

this are relatively small. They have high metabolic rates when active and, therefore, have high rates of energy consumption.

Some bats feed at night and go into torpor in daylight.

Chickadees and hummingbirds feed during the day and often go into torpor on cold nights.

Examples of endotherms

Comprehension CheckCategorize each of the following scenarios as an example of daily torpor(D), estivation(E), or hibernation(H).

Some types of snails become inactive when the climate becomes too hot or dry.A squirrel becomes inactive in the coldest parts of winter.A bat becomes inactive during the day

and hunts at night.Bears eat large amounts of food to store energy and become inactive in the winter.

E

D

H

H