Unit 4.1 Regulation & Feedback Mechanisms

Regulation & Feedback Mechanisms

1. Animal Form & Function at All Levels of Organization
- Evolution of Animal Size & Shape
- Exchange with the Environment
- Hierarchical Organization of Body Plans
- Coordination & Control

2. Feedback Control
- Regulating and Conforming
- Homeostasis

3. Thermoregulation
- Endothermy and Ectothermy
- Variation in Body Temperature
- Balancing Heat Loss and Gain
- Acclimatization
- Physiological Thermostats

4. Energy Requirements
- Energy Allocation and Use
- Quantifying Energy Use
- Minimum Metabolic Rate &
- Thermoregulation
- Influences on Metabolic Rate
- Torpor and Energy Conservation

natural, adaptation, relative

Animal Form & Function at All Levels of Organization
● Animal species obtain nutrients and oxygen, fight off infection, survive to produce offspring, and share other basic requirements
● Vary in anatomy due to ______ selection and _______
○ Natural selection favors those variations in a population that increase ______ fitness
○ Evolutionary adaptations that enable survival vary among environments and species but frequently result in a close match of form to function

Anatomy

➔ Study of the biological structure

Physiology

➔ Study of the biological function
➔ Examining anatomy provides clues to this

Evolution of Animal Size & Shape

Physical laws that govern strength, diffusion, movement, and heat exchange limit the range of animal form

1000, ray

1. Water is _____x denser than air and is far more viscous
- Limits possible animal shapes for fast swimmers
○ Any bump on an animal body’s surface that causes drag would impede it more than a flier or runner
○ Tuna and other fast __-finned fishes can swim at speeds up to 80 km/hr
○ Sharks, seals, penguins, dolphins

Fusiform

➔ Streamline shape that is tapered on both ends
➔ An example of convergent evolution in speedy vertebrate swimmers

size, Thicker, locomotion

2. Increase in body dimensions with regard to maximum ___
● _______ skeletons are required to maintain adequate support
○ Affects internal skeletons (vertebrates) and external skeletons (insects and arthropods)

● Muscles required for ________ represent a larger fraction of the total body mass
○ Mobility will become limited at some point
○ Tyrannosaurus rex: some say top running speed is that of an Olympic sprinter (30km.hr) while others say it was at best a fast walker

aqueous, plasma

Exchange with the Environment
● Animals must exchange nutrients, waste products, and gases with their environment
○ Imposes an additional limitation on body plans
● Exchange occurs as substances dissolved in an ________ solution move across the _______ membrane of each cell
1. Unicellular
2. Multicellular

Amoeba

Unicellular
● _______ has a sufficient membrane surface area in contact with environment to facilitate exchange

Rate, surface, Amount, volume

Multicellular
● Multicellular organization only works if every cell has access to suitable aqueous environment
■ ____ of exchange is proportional to membrane _______ area
■ ______ of material must be exchanged is proportional to total body _____
1. Simple animals (hydra, tapeworm)
2. Complex animals

Hydra, sac, gastrovascular, intestinal

Simple animals
○ ____ has a ___like body plan and a body only 2 cell layers thick
■ Its _________ cavity opens to the external environment, both outer and inner layers are constantly bathed in pond water

○ Parasitic tapeworm’s thin and flat shape places most cells in direct contact with its particular environment (________ fluid)

cells, decreases, branched, interstitial, circulatory

Complex animals
○ Increasing the number of ____ __________ the ratio of surface area to total volume
■ SA:TV of whale is hundreds of thousands of times smaller than of a water flea

○ Evolutionary adaptations enable sufficient exchange with the environment are often specialized surfaces that are _______ or folded
■ Branching and folding greatly increases SA
■ In humans, exchange surfaces for digestion, respiration, and circulation are 25X larger than skin

○ Contain ______ fluid and _______ fluid (blood)

1. Excretory
2. Digestive
3. Circulatory
4. Respiratory

Interstitial fluid

➔ From Latin for “stand between”
➔ Fluid that fills the space between cells in animals

External, sensory, digestive, filtration, land

Complex body advantages
○ Offers numerous benefits such as:
1. ______ skeleton protects against predators
2. ______ organs provide detailed information
on surroundings
3._______ organs can break down food
gradually, controlling release of stored energy
4. Specialized _______ systems can control
internal fluid that bathes cells
○ Complex body plan is advantageous
for _____ animals where external environment is highly variable

emergent

Hierarchical Organization of Body Plans
● Cells form a working body through their ________ properties, which arise from successive levels of structural and functional organization
1. Tissues
2. Organs
3. Organ systems

Tissues

➔ Groups of cells with similar appearance and common function

Organs

➔ Different types of tissues are further organized into these
◆ Simplest animals (e.g. sponges) lack true tissues and organs

Organ system

➔ Groups of organs that work together
◆ Skin is an organ of the integumentary system, which protects against infection and regulates body temperature

Digestive system

● Main components:
Mouth, pharynx, esophagus, stomach, intestines, liver, pancreas, anus

● Main functions:
Food processing (ingestion, digestion, absorption, elimination)

Circulatory system

● Main components:
Heart, blood vessels, blood

● Main functions:
Internal distribution of materials

Respiratory system

● Main components:
Lungs, trachea, other breathing tubes

● Main functions:
Gas exchange (uptake of oxygen, disposal of carbon dioxide)

Immune & Lymphatic system

● Main components:
Bone marrow, lymph nodes, thymus, spleen, lymph vessels

● Main functions:
Body defense (fighting infections & virally induced cancers)

Excretory system

● Main components:
Kidneys, ureters, urinary bladder, urethra

● Main functions:
Disposal of metabolic wastes, regulation of osmotic balance of blood

Endocrine system

● Main components:
Pituitary, thyroid, pancreas, adrenal, & other hormone- secreting glands

● Main functions:
Coordination of body activities (e.g., digestion & metabolism)

Reproductive system

● Main components:
Ovaries/testes & associated organs

● Main functions:
Gamete production, promotion of fertilization, & support of developing embryo

Nervous system

● Main components:
Brain, spinal cord, nerves, sensory organs

● Main functions:
Coordination of body activities, detection of stimuli, & formulation of responses to them

Integumentary system

● Main components:
Skin and its derivatives (hair, claws, sweat glands)

● Main functions:
Protection against mechanical injury, infection, dehydration, and thermoregulation

Skeletal system

● Main components:
Skeleton (bones, tendons, ligaments, cartilage)

● Main functions:
Body support, protection of internal organs, movement

Muscular system

● Main components:
Skeletal muscles

● Main functions:
Locomotion and other movement

more, enzymes, sugar, emergent, specialization

Hierarchical Organization of Body Plans
● Many organs have ___ than one physiological role
○ Pancreas produce ______ for the digestive system and regulate ____ level in the blood for the endocrine system

● Viewing the body’s organization from bottom-up (cells to organ system) reveals ________ properties, top-down view of the hierarchy reveals multilayered basis of ___________

● Organ systems include specialized organs made of specialized tissues and cells
○ Top-down view of human digestive system:

tissue

Hierarchical Organization of Body Plans
● Specialized and complex organ systems are built from a limited set of cell and ______ types
○ Lungs and blood vessels have different functions but are lined with the same basic type of cell and therefore share properties

outside, cavities, junctions, barrier, interfaces

Epithelial tissue
● Epithelia (plural), epithelium (singular)
● Cover the _______ of the body and line organs
and _______ within the body
● Are closely packed (often with tight _______) and function as a ______ against mechanical injury, pathogens, and fluid loss
● Also form active ________ with the environment
○ Nasal passage epithelium is crucial for olfaction, the sense of smell

Types of tissue

1. Epithelial tissue
- Squamous
- Cuboidal
- Columnar

2. Connective tissue
- Collagenous
a. Fibrous/Dense
b. Loose
- Specialized
a. Adipose
b. Bone
c. Blood
d. Cartilage

3. Muscle tissue
- Skeletal
- Smooth
- Cardiac

4. Nervous tissue
- Glia
- Neurons

Epithelial tissue

1. Squamous
- Simple squamous
- Stratified squamous

2. Cuboidal
- Simple cuboidal
- Stratified cuboidal

3. Columnar
- Simple columnar
- Stratified columnar
- Pseudostratified columnar

plate, diffusion, vessels, sacs

Simple squamous
➔ Single layer of ____like cells
➔ Function in exchange of material by _______ as it is thin and leaky
➔ Lines blood _____ and air ___ of lungs where diffusion of nutrients and gases is essential

generates, basal, abrasion, skin, mouth, anus, vagina

Stratified squamous
➔ Multilayered and _______ rapidly
➔ New cells and formed by division near the ____ surface push outward, replacing cells that slough off
➔ Found on surfaces subject to _______ such as outer ___, linings of the _____, ____, and ______

secretion, kidney, glands

Cuboidal
➔ Dice-shaped cells that specialize in _______
➔ Make up the epithelium of _____ tubules and many ______ (e.g., thyroid and salivary glands)

secretion, absorption, intestines

Simple columnar
➔ Large, brick-shaped cells are often found where _______ or active ______ is important
➔ Lines the ______, secreting digestive juices and absorbing nutrients

nuclei, ciliated, respiratory

Pseudostratified columnar
➔ Single layer of cells varying in height and the position of their _____
➔ In vertebrates, pseud. strat. epithelium of ______ cells forms mucous membrane that lines portions of the ________ tract
◆ Beating cilia sweep film of mucus along the surface

Polarity of epithelia

➔ All epithelia are polarized - have two different sizes

Apical surface

◆ Faces the lumen (cavity) or outside of the organ is exposed to fluid or air
◆ Specialized projections often cover this surface (microvilli in small intestine epithelium)

Basal surface

◆ Opposite of the apical surface

sparse, extracellular matrix, fibroblasts, macrophages

Connective tissue
● Consisting of a ______ population of cells scattered throughout _________ ______
● Holds tissues and organs together in place
○ Matrix generally consists of a web of fibers embedded in a liquid, jellylike, or solid foundation
○ Contain ______ (secrete fiber proteins) and ________ (engulf foreing particles and cell debris through phagocytosis)

Connective tissue fibers

1. Collagenous
2. Reticular
3. Elastic

● Collagenous and reticular fibers prevent skin from being pulled far from the bone
● Elastic fibers restore the skin to its original shape

Collagenous fibers

➔ Provide strength and flexibility

Reticular fibers

➔ Join connective tissue to adjacent tissues

Elastic fibers

➔ Make tissues elastic

Connective tissue

1. Collagenous
a. Fibrous/Dense
b. Loose

2. Specialized
a. Adipose
b. Bone
c. Blood
d. Cartilage

collagenous, tendons, ligaments

Fibrous connective tissue
➔ Dense with _______ fibers
➔ Is found in ______ (attaches muscle to bones) and _______ (connect bones at joints)
➔ May be further subdivided into:
◆ Dense regular
◆ Dense irregular

widespread, epithelium

Loose connective tissue
➔ Most ________ connective tissue in vertebrates
➔ Bind _______ to underlying tissues and holds organs in place
➔ Named after loose weave of its fibers (includes the 3 types)
➔ Found in the skin and throughout the body

cells, insulates, fuel, droplet

Adipose tissue
➔ Specialized connective loose tissue that stores fat in adipose ____ distributed throughout its matrix
➔ Pads and ______ the body and stores ___ as fat molecules
➔ Each adipose cell contains a large fat ______ that swells when at is stored and shrinks when the body uses that fat as fuel

Mineralized, blasts, collagen, ns, canal

Bone
➔ ________ connective tissue

➔ Osteo____: deposit a matrix of ______. Calcium, magnesium, and phosphate ions combine into a hard mineral with the matrix.

➔ Osteo__: microscopic structure of hard mammalian bone consists of repeating units of these
◆ Each has concentric layers of the mineralized matrix, which are deposited around a central ____ containing blood vessels and nerve

plasma, erythrocytes, leukocytes, platelets

Blood
➔ Has a liquid extracellular matrix called ______ (water, salts, & dissolved proteins)
➔ Suspended in plasma are
◆ _______ (RBCs) - carry oxygen
◆ ________ (WBCs) - defense
◆ cell fragments (_____) - in blood clotting

chondroitin, Chondrocytes, embryos, disks

Cartilage
➔ Contains collagenous fibers embedded in a rubbery protein-carbohydrate complex (_______ sulfate)
➔ _________ secrete the collagen and chondroitin sulfate, which make cartilage strong yet flexible support material
➔ Skeletons of many vertebrate ______ contain cartilage that is replaced by bone as it matures
◆ Cartilage remains in some locations, such as the ___ that act as cushions between vertebrate

actin, myosin

Muscle tissue
● Responsible for nearly all types of body
movement
● Consist of filaments containing proteins ____ and ____, which together enable muscles to contact

striated, voluntary, bundles, fusion, sarcomeres, size

Skeletal muscle
➔ Also known as ______ muscle
➔ Responsible for _______ movements
➔ Consists of ____ of long cells that
are muscle fibers
◆ Skeletal muscle fibers form by the _____ of many cells, resulting in multiple nuclei in each muscle fiber
◆ Arrangement of contractile units (______), along the fibers gives the cells a striated appearance
➔ In adult mammals, building muscle increases ___ but not number of muscle fibers

bladder, internal, spindle, involuntary

Smooth muscle
➔ Lacks striations, found in the walls of the digestive tract, urinary _____, arteries, and other internal organs
➔ Cells are ______-shaped
➔ _______ body activities, such as churning of stomach and construction of arteries

contractile, striated, branched, intercalated

Cardiac muscle
➔ Forms the ______ wall of the heart
➔ _____ and has similar contractile properties to skeletal muscle
➔ Unlike skeletal muscle, has ______ fibers that interconnect via _______ disks, which relay signals from cell to cell and help synchronize heart contraction

brain

Nervous tissue
● Receipt, processing, and transmission of information
● Contains
○ Neurons (nerve cells), which transmit nerve impulses
○ Glial cells support nerve cells
● A concentration of nervous tissue forms a ___, an information-processing center

body, dendrites, axons

Neurons
➔ Basic units of the nervous system
➔ Receives nerve impulses from other neurons via its cell ___ and multiple extensions called ______
➔ Transmits impulses through ____

modulate

Glia
➔ Various types of glia help nourish, insulate, and replenish neurons
➔ Can also ______ neuron function

stimuli

Coordination & Control
● Animals have two major systems for coordinating and controlling responses to ______:
1. Endocrine
2. Nervous

bloodstream, all

Endocrine system
➔ Signaling molecules released into the ________ by endocrine cells to all locations in the body

routes, specific

Nervous system
➔ Neurons transmit signals along dedicated ______ connecting ______ locations in the body

Signal, Trans, Speed, Duration

Coordination & Control

● Pathway in each system is the same regardless of whether the signal’s ultimate target is at the other end of the body or a few cell diameters away

● Differ in:

1\. ____ type

2\. ____mission

3\. ______

4\. ______

● Two systems work in close coordination and help maintain a stable internal environment

gradual, growth, repro, metabolic, digestion

Endocrine system
● Well adapted for coordinating ______ changes that affect the entire body (_____, development, ____duction, ______ processes, and _____)

molecules, long, receptors

Hormones
➔ Signaling _______ that are broadcast throughout the body
➔ ___-lasting effects as they can remain in the bloodstream for minutes or even hours
➔ Depending on cell ______, hormone may have an effect in just a single location or in sites throughout the body

Thyroid-stimulating hormone (TSH)

➔ acts solely on cells in the thyroid gland and in turn, release thyroid hormone which increases oxygen consumption and heat production

neurons, muscle, glands, pathway, type, immediate

Nervous system
● Nerve impulses can act on other _______, on _____ cells, and _____ that produce secretions

● Unlike endocrine, conveys information by the _____ the signal takes
○ A person can distinguish different musical notes because each note’s frequency activates neurons in the ear that connect to slightly different locations in the brain

● Usually involves more than 1 ___ of signal
○ Nerve impulses travel long distances along axons as changes in voltage
○ In contrast, passing info from one neuron to another often involve very short-range chemical signals

● Well suited for directing _______ and rapid responses to the environment, such as reflexes and other rapid movements

Feedback control

1. Regulating and Conforming
2. Homeostasis
- Mechanisms
- Feedback control
- Alterations

internal, Otter

Regulator
➔ Animal uses _____ mechanisms to control internal change in the face of external fluctuation
◆ Ex. River ___ - regulator for temperature, body temperature is largely dependent on surrounding water

external, Bass, temperature, crabs, solute

Conformer

➔ Animal allows its internal condition to change in accordance with _____ changes in particular variables

◆ Ex. Largemouth ____ - conforms to the ________ of the lake it inhabits

➔ Does not need to involve changes in an internal variable

◆ Marine invertebrates (ex. Spider ____)

● Internal ____ concentration conforms to stable salinity of their environment

interstitial

Regulating and Conforming
● An animal may regulate some conditions and conform to the environment for other variables
○ Ex. Largemouth Bass
■ Conforms to the temperature of the water
■ Regulates the solute concentration in its blood and ______ fluid

steady, constant, temperature, pH, glucose

Homeostasis ● Maintenance of internal balance or a “_____ state” ○ ______ internal environment even when the external environment changes significantly ● Humans maintain a constant body _____, blood , __and blood _____ concentration

Mechanisms

1. Set point
2. Stimulus & sensor
3. Response

set point

● Homeostatic control system in animals maintains a variable at or near a particular value known as the ____ ______

stimulus, sensor

● Fluctuations in the set point serves as the _____ and is detected by a _____

response

● Sensor signals a control center which triggers a ______
○ Physiological activity that helps return the variable to set point

Feedback control

1. Negative feedback
2. Positive feedback

reduces, Nervous, sweating

Negative feedback
➔ Control mechanisms that _____ or “damps” stimulus
◆ Ex. Exercise increases body temperature
● _____ system triggers ______
● Evaporation of sweat cools the body

amplifies, pressure, contract,

Positive feedback
➔ Control mechanisms that ______ stimulus
◆ Ex. Childbirth
● ______ of baby’s head against receptors near uterus stimulates uterus to _______
● Contractions result in greater pressure until the baby is born
➔ Helps drive homeostatic processes into completion
◆ Do not play a major role in homeostasis

dynamic, oppose

Feedback control
● Homeostasis is a ______ equilibrium
○ Interplay between external factors that tend to change the internal environment
○ Internal control mechanisms _____ such changes

moderates, range, adaptations

**Feedback control**

* Homeostasis _____ but doesn’t eliminate changes in the internal environment
* Fluctuations are greater if a variable has a normal ____ rather than a set point
* Refers to an upper and lower limit
* Homeostasis is enhanced by ______ that reduce fluctuations

Alterations

1. Regulated changes
2. Circadian rhythm

stages, puberty, cyclic, menstrual

● Regulated changes in the internal environment are essential to normal body functions
○ Set points and normal ranges for homeostasis can change under various circumstances
● Regulated changes can be in accordance with _____ of life
○ Ex. There is a radical shift in hormone balance that occurs during puberty
● Regulated changes can be ____
○ Ex. Variation in hormone levels responsible for a woman’s ______ cycle

Circadian rhythm, 24, light, temperature, External, lag

● Cyclic alterations in all animals and plants reflect a _______ _____
○ Set of physiological changes that occur roughly every ___ hours
○ Intrinsic to the body
■ Normally coordinated with the cycle of ____ and
darkness in the environment
○ Observed in the cyclic rise and fall of human ________ in a 24-hour period
○ ______ stimuli can reset the biological clock, but the effect is not immediate
■ Ex. Flying across several time zones results in jet ___
● Mismatch between circadian rhythm and local environment

Thermoregulation

1. Endothermy and Ectothermy
2. Variation in Body Temperature
3. Balancing Heat Loss and Gain
- Insulation
- Circulatory adaptations
- Cooling by evaporative heat loss
- Behavioral responses
- Adjusting metabolic heat production
4. Acclimatization
5. Physiological Thermostats

maintain, enzymatic, fluidity, sensitive

Thermoregulation
● the process by which animals ______ their body temperature within a normal range
● Body temperatures outside normal range can:
○ reduce the efficiency of _______ reactions
○ alter the _____ of cellular membranes
○ affect other temperature-______ biochemical processes

Source of heat

- Endothermy
- Ectothermy

Stability of body temperature

- Poikilothermy
- Homeothermy

exclusive

● Endothermy and ectothermy are NOT mutually _____.

internal

Endotherms
➔ Heat is generated by _______ metabolism
➔ can maintain a stable body temperature even if the environmental temperature fluctuates
➔ Examples include
◆ Mammals (Humans)
◆ Birds
◆ Some fishes and insects

external, food, fluctuations

Ectotherms
➔ Heat comes from _____ sources /
environment
➔ adjust their body temperature by behavioral means (basking in the sun)
● Many nonavian reptiles
● Fishes
● Most invertebrates

➔ Generally need to consume less ____ than endotherms of same size (advantageous when resources are scarce)
➔ Tolerate larger _______ in internal temperature
➔ Effective and successful strategy as observed in the abundance and diversity of ectotherms

source, stability

Variation in Body Temperature
● There is NO fixed relationship between the ______ of heat (endothermy/ectothermy) and the ______ of body temperature (poikilotherm/homeotherm).
● Ectotherms do NOT necessarily have low body temperatures
1. Poikilotherm
2. Homeotherm

Poikilotherm

➔ Body temperature varies with its environment (Greek poikilos = varied)

Homeotherm

➔ Relatively constant body temperature

Misconception

○ Ectotherms = “cold-blooded” &
endotherms = “warm-blooded”
(this is wrong!!)
○ Avoid the terms “cold-blooded” and “warm-blooded” because they are misleading

Thermoregulation

Balancing Heat Loss and Gain
● ________ depends on an animal’s ability to control its exchange of heat with the environment through any of the four processes:
1. Radiation
2. Evaporation
3. Convection
4. Conduction

=, HIGH, integumentary

Balancing Heat Loss and Gain

* The goal is to have rate of heat gain __ rate of heat loss
* Heat is always transferred from ____ → LOW temperature
* Several of these mechanisms involve the _______ system, skin, hair, nails/claws/hooves