Biol2001 Midterm Ii

Front 1

Coordination depends on (2)

Back 1

ENDOCRINE SYSTEM
NERVOUS SYSTEM

Front 2

Endocrine system

Back 2

-Transmits chemical signals (hormones) via blood to receptive cells throughout the body
-Slow acting but long-lasting effects

Front 3

Nervous system

Back 3

-Transmits electrical signals (nerve impulses) along chains of neurons
-Fast-acting, short-lasting effects

Front 4

Ways to maintain internal enviro (2)

Back 4

Regulating
Conforming

Front 5

REGULATOR

Back 5

-Uses internal control mech'ms to moderate internal change in face of external fluctuation
-Most birds and mammals

Front 6

CONFORMER

Back 6

-Internal condition allowed to vary with certain changes in external enviro
-Most invertebrates, fishes, amphibians, non-avian reptiles

Front 7

HOMEOSTASIS

Back 7

-Process by which animal maintains internal balance regardless of external changes
-Mechanisms moderate changes in internal enviro.

Front 8

Homeostasis mechanisms

Back 8

-Fluctuations above or below a SET POINT serve as STIMULUS detected by a SENSOR triggering a RESPONSE returning variable to set point
-Mostly NEGATIVE FEEDBACK

Front 9

Alterations in homeostasis

Back 9

Set points and normal ranges can change showing cyclic variation (seasons, age)
-ACCLIMIZATION: gradual adjustment to changes in external enviro during lifetime

Front 10

THERMOREGULATION

Back 10

-Process by which animals maintain internal temp within tolerable range
-Maintaining rates of heat gain that equals rates of heat loss
-Important for: enzyme activity, protein integrity, membrane properties

Front 11

Thermoregulation sources of heat

Back 11

Internal metabolism and external environment

Front 12

ENDOTHERMIC animals

Back 12

-Generate heat by metabolism, birds and mammals
-Active at greater range of external temps
-More energetically expensive

Front 13

ECTOTHERMIC animals

Back 13

-Gain heat from external sources, most invertebrates, fishes, amphibians, non-avian reptiles
-Tolerate greater variation in internal temp

Front 14

POIKILOTHERM vs. HOMEOTHERM

Back 14

-Refers to consistency of body temperature
P: Body temp varies with enviro, usually ECTO
H: Body temp relatively constant, usually ENDO

Front 15

Heat exchange, physical processes (4)

Back 15

CONDUCTION: contact
CONVECTION: air or liquid
RADIATION: without contact
EVAPORATION: removal of heat from wet surface

Front 16

Endothermy +/-

Back 16

(+):
-More active lifestyle, year round
-Greater endurance
-Tolerate temp fluctuations better
(-):
-Energetically costly
-Need to eat more food

Front 17

Reducing Heat Loss (3)

Back 17

Insulation
Feathers, Hair, Goosebumps, Blubber
Circulatory adaptations

Front 18

Insulation

Back 18

-Reduce heat flow from animal to enviro
-Reduced energy cost
-Integumentary system (outer covering)
-Protection from injury, dessication, UV

Front 19

PILOERECTION

Back 19

Hair follicle muscles contract closing small poles--> reduced heat loss

Front 20

Circulatory adaptations for reducing heat loss (3)

Back 20

VASODILATION: enlargement of blood vessel diameter increasing blood flow to a part of the body, increased transfer of body heat from skin to enviro
VASOCONSTRICTION: reducing diameter of blood vessel to reduce blood flow to part of body, decreased transfer of body heat to enviro
COUNTER-CURRENT HEAT EXCHANGERS: 2 channels close to each other but blood flows in opposite directions--> reduced heat loss, blood temp loses heat as moves away from heart but brought back towards the heart and some heat is conserved

Front 21

Cooling

Back 21

-Evaporative heat loss across skin and when breathing
-Water absorbs heat when evaporates (sweating)
-Water on surface helps cooling off
-Panting, licking

Front 22

Behavioural responses for thermoregulation

Back 22

-Immersion in water
-Basking in sun
-Migrating
-Hibernating

Front 23

Adjustment for metabolic heat production (3)

Back 23

-Endotherms vary heat production to counteract heat loss
1) THERMOGENESIS: production of heat by increased muscle activity (shivering & moving)
2) NON-SHIVERING THERMOGENESIS: certain hormones cause mito to increase metabolic activity--> heat
3) BROWN FAT: rapid heat production specialization

Front 24

Human thermoregulation

Back 24

-Hypothalamus = "thermostat", has temperature sensors
-Can signal nervous system to signal constriction or dilation of capillaries and thermogenesis

Front 25

ACCLIMATION

Back 25

-Gradual process involving gradual shifts in set point of hypothalamus with seasons and age
-Adaptations include
>change in thickness of fur, feathers (ENDO)
>shift of tolerance levels (END&ECT)
>cellular changes, lipid and cryoprotectant (ECTO antifreeze) production

Front 26

Avoiding cold

Back 26

TORPOR: reduced activity and metabolic rate for short duration to conserve energy
HIBERNATION: long-term torpor triggered by severe enviro conditions to avoid cold and food shortage

Front 27

Avoiding heat

Back 27

ESTIVATION: periods of torpor to avoid desert heat

Front 28

Need energy for...(5)

Back 28

Growth
Repair
Activity
Temperature regulation
Reproduction

Front 29

BIOENERGETICS

Back 29

Overall flow and transformation of energy through an animal, determines nutritional needs

Front 30

Factors affecting energy requirements

Back 30

-Size, age, sex
-Genetics, hormones
-Activity
-External temp, O2 availability
-Food

Front 31

METABOLIC RATE

Back 31

Amount of energy an animal uses in a unit of time
-In joules or calories
-Indirectly measured from O2 consumption or CO2 production

Front 32

ENDOTHERMY vs. ECTOTHERMY bioenergetic strategies

Back 32

ENDO: Body temp maintained by metabolic heat, high metabolic rate
ECTO: Body temp maintained by external sources, lower metabolism

Front 33

Body size and metabolic rate

Back 33

Small--> high meta rate, eat more food and burn more
-Risk heat loss faster with larger SA:V

Front 34

BASAL METABOLIC RATE (BMR)

Back 34

Metabolic rate of non-growing, non-stressed endotherm at rest

Front 35

STANDARD METABOLIC RATE (SMR)

Back 35

Metabolic rate of fasting, non-stressed ecotherm at rest @ particular temp

Front 36

Factors influencing metabolic rate (2)

Back 36

Body size
Activity

Front 37

Body size and metabolic rate

Back 37

-Inversely related
-Higher metabolic rate--> higher O2 delivery rate, breathing rate, heart rate, and greater blood volume

Front 38

Activity and metabolic rate

Back 38

Maximum metabolic rate an animal can sustain is inversely related to the duration of the activity
-Are correlated for both ENDO and ECTO

Front 39

Energy budgets

Back 39

-Differ between species
-Use energy and materials in food in diff ways depending on enviro
-Use of energy partitioned to BMR/SMR, activity, thermoregulation, growth and reproduction

Front 40

Evolution of skeletal systems

Back 40

Solution to the lack of rigidity/support/shape in animal cells

Front 41

ARCHIMEDES PRINCIPLE

Back 41

A fluid exerts an upward force equal to its displaced volume (weight)

Front 42

Support in water vs. land

Back 42

-Supportive force of air is only 1/1000 that of water on aquatic animals' body
-Physical constraint--> evolution of skeletal sys, body size and modes of locomotion

Front 43

3 main functions of skeletons

Back 43

1) Support
2) Protection
3) Movement

Front 44

3 main types of skeletons

Back 44

1) Hydrostatic, lack hard parts
2) Exo, external hard parts
3) Endo, internal hard parts

Front 45

Hydrostatic skeleton

Back 45

-Fluid under pressure in closed body compartment
-Controls body form and movement
-Muscles change shape of cavities
-Cnidarians, flatworms, nematodes, annelids
-Not suitable for terrestrial animals that have limbs
-PERISTALSIS: rhythmic waves of muscle contractions for movement on land

Front 46

Exoskeletons

Back 46

-Hard encasement/casing deposited on animal's surface
-Support and protection
-Molluscs: CALCIUM CARBONATE external shell secreted by mantle
-Arthropods: jointed exoskeleton is a cuticle consisting of CHITIN

Front 47

Endoskeletons

Back 47

-Hard supporting elements buried in soft tissue
-Sponges: SPICULES
-Echinoderms: OSSICLES, magnesium carbonate plates and calcium carbonate crystals
-Chordates: cartilage or bone

Front 48

Mammalian skeleton

Back 48

->200 bones
-Some bones fused, others connected at joints by ligaments allowing movement

Front 49

Human skeleton

Back 49

AXIAL SKELETON: skull, ribcage, backbone
APPENDICULAR SKELETON: pectoral girdle (clavicle+scapula), pelvic girdle, limbs

Front 50

Joints

Back 50

Different types allow for movement in different directions

Front 51

Principle of Scaling or Allometry

Back 51

-As body gets larger, weight increases as a cube while cross-sectional area increases as a square
-Skeletal mass constrains body size
-Large animals have thicker bones

Front 52

Limb structure and position

Back 52

-Larger animals: pillar-style bones, "I-beam"
-In terrestrial animals, leg position relative to body determines the weight the legs can bear

Front 53

Muscles

Back 53

-Activity is a response to input from the nervous sys
-Action is always to contract
-Mechanical forces generated for movement
-Manipulation of objects
-Power locomotion, blood circulation, movement of food, respiration
-Protein components: ACTIN & MYOSIN

Front 54

Skeletal Muscle (Speed, endurance, control, striations)

Back 54

Fast
Low
Voluntary
Yes

Front 55

Smooth muscle (speed, endurance, control, striations)

Back 55

Slow
High
Involuntary
No

Front 56

Cardiac muscle (speed, endurance, control, striations)

Back 56

Variable
Intermediate (good endurance)
Involuntary
Yes

Front 57

Vertebrate skeletal muscles

Back 57

-Attached to bones
-Antagonistic pairs
-Paired muscles function together to move bones

Front 58

Skeletal muscle structure

Back 58

-Long FIBERS, each a single cell, parallel to length of the muscle
-Each muscle fiber = bundle of longitudinal MYOFIBRILS
-Each myofibril has ACTIN and MYOSIN filaments
-SARCOMERE: functional unit

Front 59

Sliding-filament model of muscle contraction

Back 59

-Filaments slide past each other longitudinally--> overlap between thin and thick filaments
-Sliding based on interaction between thin actin and thick myosin filaments
-Myosin "head" binds to actin pulling actin toward sarcomere centre
-ATP must be generated to sustain muscle contraction

Front 60

Neural control of muscle tension

Back 60

-Muscle contraction is GRADED, extent and strength of contraction can be voluntarily altered
-2 basic mechanisms for producing graded contractions
1) vary contracting fiber #s
2) varying rate of stimulation

Front 61

SLOW-TWITCH MUSCLE FIBERS

Back 61

-Contract more slowly
-Sustain long contractions
-Myoglobin-rich
-Aerobic metabolism
-Long-distance, endurance

Front 62

FAST-TWITCH MUSCLE FIBERS

Back 62

-White
-Contract more rapidly
-Short bursts of powerful contraction, sprinting
-Anaerobic metabolism
-Poor endurance

Front 63

Smooth muscle

Back 63

-Myosin scattered in cytoplasm
-Actin anchored
-Activated by autonomic nervous system
-Slow contraction over greater length
-Walls of hollow organs

Front 64

Cardiac muscle

Back 64

-Vertebrate hearts
-"Pacemaker" muscle cells fire rhythmically @ set rate regulated by nervous sys
-Electrical signals pass
-Involuntary
-Strong contractions, slow to fatigue

Front 65

Insect flight muscles

Back 65

-Similar to vertebrate skeletal muscles
-Highest metabolic rate of all muscle tissues, highest rate of contraction
-Contraction--> upstroke and downstroke--> thrust

Front 66

Problems associated with locomotion

Back 66

In water and air: How to resist gravity and how to move forwards
On land: How to support the body

Front 67

Solutions to problems with locomotion in water

Back 67

-Maintaining buoyancy
-Minimize friction/drag
-Generate lift & thrust

Front 68

Solutions to problems with locomotion in air

Back 68

-Generating lift and thrust
-Minimize friction/drag

Front 69

Solutions to problems with locomotion on land

Back 69

-Bone strength
-Placement of limbs

Front 70

Two pairs of opposing forces

Back 70

Gravitational pull vs. lift (BUOYANCY)
Drag vs. Thrust (Fwd movement)

Front 71

Buoyancy

Back 71

-Neutral buoyancy possible with hydrostatic skeletons (tissue density=marine water density), no E required to remain suspended
-Animals with rigid skeletons are denser than water--> evolved adaptations for buoyancy:
>loss or reduction of rigid skeleton
>less bony material
>buoyancy devices: gas-filled floats, gas-filled swim bladder, lipid-filled liver

Front 72

Thrust and Drag

Back 72

-To move fwd, thrust>drag
-Drag affected by:
>Fluid viscosity and density
>Body shape and smoothness

Front 73

Modes of swimming/movement

Back 73

-Body undulation (worms, fishes, leeches)
-Fin oscillation (fishes)
-Rowing (water boatmen, ducks)
-Hydrofoils (penguins, marine turtles, dolphins, sharks)
-Jet propulsion (squids, jellyfish)

Front 74

Locomotion in air

Back 74

-Flying: gliding&soaring, flapping&powered flight
-Lift vs gravity & thrust vs. drag
-Gravity resisted with weight reduction, hollow bones, no teeth, no bladder, one ovary
-Airflow over convex wings--> lift
-Drag reduced by streamline body and wing shape

Front 75

Modes of flying (2)

Back 75

1) Gliding and soaring: updrafts used for lift, power from thermal air currents, energy efficient, tend to be predators
2) Flapping and hovering: generates lift and thrust, power from flight muscles, energetically expensive

Front 76

Locomotion on land

Back 76

-Requires support of body weight against gravity
-Center of gravity between legs: 'push up' position, support from bones and muscles, inefficient
-Center of gravity over legs: 'graviportal' position, support from bones, more efficient

Front 77

Modes of locomotion on land (7)

Back 77

With limbs:
-walking
-running
-hopping
-jumping
Body on substrate:
-crawling
-sliding
-slithering

Front 78

Energy costs of locomotion

Back 78

-Energetically expensive, E required to do work (force moving and object a certain distance)
-Cost depends on: mode, distance, and enviro
-Estimated by O2 consumption/CO2 production

Front 79

Allometry of locomotion

Back 79

SPEED:
-Larger animals locomote faster than smaller animals
-flying>running>swimming for animals of the same size
ENERGY COST
-Larger animals have lower energy costs
-swimming<flying<running

Front 80

Home range

Back 80

-Large animals have larger home ranges, influenced by diet and resource availability

Front 81

Migrations

Back 81

-Long distance seasonal movements to avoid harsh enviro
-Reproductive migrations

Front 82

Relationship between size and metabolic rate

Back 82

-Larger animals have a higher metabolic rate
-Smaller animals have a greater metabolic rate with respect to body size (per unit of mass)

Front 83

Animal stages of eating

Back 83

Ingestion
Digestion
Absorption
Elimination

Front 84

3 nutritional needs

Back 84

-Chemical energy for cellular processes
-Raw materials (organic molecules) for biosynthesis
-Essential nutrients

Front 85

Metabolism chemical equation

Back 85

O2+C-based cmpds -->
CO2 + H2O + E

Front 86

Nutrient classes and comparison of E provided

Back 86

lipids/fats>protein=carbs

Front 87

Carbohydrates

Back 87

-Simple molecules--> energy obtained rapidly
-Macromolecules broken down more slowly
-Excess stored as glycogen in liver and skeletal muscles
-55% of daily calorie needs

Front 88

Proteins function and in diet

Back 88

-Main building block of tissues(muscles, skin, connective tissue)
-Enzymes, support, transport, movement, storage, immunological ...many other roles
-20AA, 8-9 essential obtained from food
-Animal food = best source of proteins, all 20 AAs
-Excess stored as fat
10%-15% of daily calorie needs

Front 89

Lipids/Fats

Back 89

-Complex molecules: glycerol + FA chains
-E rich
-Animals can synthesize MOST FAs
-Essential FAs can't be manufactured, must be ingested- unsaturated fats
-Should not exceed 30% of daily calories
-Stores most excess E as fat in fatty tissues

Front 90

Vitamins

Back 90

-Organic, required in small amounts
-13 essential
-H2O & fat soluble
-For coenzymes in metabolic pathways, 'anti-oxidants', collagen synth, bones, visual pigments

Front 91

Minerals

Back 91

-Inorganic, required in small amnts
-Ca & P for bones
Fe, Mg, Zn, Cu, Se, Mo for enzymes
-Ca for muscles
-Na, K, Cl for nerves & osmotic balance
-P for ATP and nucleic acids

Front 92

Feeding types (5)

Back 92

Herbivores
Carnivores
Detritivores
Omnivores
Parasites

Front 93

Herbivores

Back 93

-Advantages: plants are abundant
-Disadvantages:
~Plants low in fats, proteins & minerals
~Toxins present
~Cellulose and lignin hard to digest
-Mollusca, Arthropoda, Echinodermata, Chordata

Front 94

Carnivores

Back 94

-Advantages: excellent nutritional balance, E-rich tissues, easy to digest
-Disadvantages:
~Difficulty finding prey
~Prey may defend self
~Toxic prey

Front 95

Body size and feeding type

Back 95

-Small with high metabolic rate--> carnivore or GRANIVORE
-Large with low metabolic rate either herbivore or carnivore

Front 96

Detritivores

Back 96

-Advantages:
~Animal tissue easier to digest
~Animal tissue balanced in nutrients
~Cheap foraging strategy
Disadvantage: fungi and bacteria (ex. BOTULIN) on food can be poisoning
-Carrion beetles, dung beetles, hyenas, vultures, ravens

Front 97

Omnivores

Back 97

-Disadvantage: can't digest cellulose and lignin
-Humans, pigs, bears, chickens, raccoons, cockroaches

Front 98

Parasites

Back 98

-Carnivorous
-Host provides essential services, nutrition and protection
-Disadvantages:
~Transfer between hosts--> incomplete life cycle
~Death of host--> die with host

Front 99

Major feeding mechanisms (4)

Back 99

1) Suspension feeding: sift particles from water
2) Substrate feeding: live in or on food
3) Fluid feeding: suck nutrient-rich fluid from host
4) Bulk feeding: consume large pieces

Front 100

Behavioural foraging mode

Back 100

Active foraging
Sit-and-wait foraging

Front 101

Active foraging

Back 101

-Move to where the food is
-Control type of food encountered
-Access to more elusive food
-Energetically $$$, carnivores can expend 5X more energy than herb of same size
-Larger home range because animal food is scarcer

Front 102

Sit-and-wait foraging

Back 102

-Food moves to the animal
-Depends on local food abundance
-Terrestrial enviro: food must be an animal and forager must be carnivore or omnivore
-Aquatic enviro: food swims or is carried in water, must be herbivore or carnivore

Front 103

Dental/beak adaptations reflecting diet & foraging mode

Back 103

Carnivore
-Scissor-like jaw to tear flesh
-Incisors, canines, premolars and molars
Herbivore
-Back molars flat for grinding
-Far reaching long jaw
Omnivore:
-Reduced canines
-Fewer pre-molars
-Larger molars than carnivores for grinding

-Teeth evolve specialization depending on the diet and behaviour of the animal

Front 104

4 stages of food processing in the gastrointestinal tract

Back 104

Ingestion: eating, chewing
Digestion: macromolecules broken down by enzymatic hydrolysis into monomers
Absorption of nutrient molecules into body cells

Front 105

Digestive compartments

Back 105

-In the GIT, animals process food in them
-Reduce risk of animal digesting own cells and tissues

Front 106

Two-way guts

Back 106

-Single opening to gastro-vascular cavity
-Sac-like
-Cnidarians and flatworms

Front 107

One-way guts

Back 107

-Most invertebrates and all vertebrates
-2 openings to the GIT
-Unidirectional movement of food
-Functional specialization of cells along the GIT

Front 108

No guts

Back 108

-GIT lost secondarily
-Adaptation for parasitism, diffusion

Front 109

Functional regions of the one-way GIT (5)

Back 109

Mouth:
-Food reception, crushing, digestion
-Accessory glands (salivary)
Esophagus: food transport and storage
Stomach: digestion
Small intestine:
-Digestion, nutrient absorption
-Accessory glands (gall bladder, liver, pancreas)
Large intestine (colon): waste processing

Front 110

Mouth

Back 110

-Food manipulation and food size reduction
-Physical and chemical breakdown starts
-Jaws & teeth/beaks/radular teeth/hooks
-Salivary glands produce saliva:
~antibacterial properties
~food lubrication
~food digestion (secretes amylase--> polysaccharide digestion)

Front 111

Esophagus/Crop

Back 111

Food transpo from mouth--> pharynx--> stomach
-Muscles at top: striated and voluntary
-Muscles further down: smooth and involuntary
Food storage
-Distensible crop (bag-like)
-Important for animals that feed irregularly and/or consume large amnts of food rapidly

Front 112

Stomach

Back 112

-Chemical digestion
-Mixing and crushing
-Lined with smooth muscle
-Secretes gastric acid: kills bacteria, breaks down extra-cellular matrix of food cells
-Secretes enzymes, PEPSIN for protein digestion
-Mucous coating to protect lining

Front 113

Small intestine

Back 113

-Small diameter, very long
-Site of chem digestion and nutrient absorption
-Lumen wall highly convoluted--> max epithelial SA
-3 sections in human: duodenum, jejunum, ileum

Front 114

Duodenum

Back 114

-First 25cm of small intestine
-Receives acid chyme from stomach
-Digestion completed with help of bile and digestive juices from gall bladder, pancreas, liver and gland cells in intestinal wall
-Peristalsis moves chyme and juices along

Front 115

Jejunum and Ileum

Back 115

-Site of absorption of nutrients and water
-Lined with villi with microvilli, increase SA
-Villi have blood and lymph vessels
-Nutrients absorbed into blood stream across epithelial cells of villi and vessels

Front 116

Large intestine (colon)

Back 116

-Large diameter but short
-Preparation of feces
-Water extraction from feces
-Feces moved along by peristalsis
-Colon houses bacteria for production of vitamins
-Rectum: feces storage prior to elimination
-Sphincter muscles @ colon entrance and exit

Front 117

Stomach and intestinal adaptations

Back 117

-HERB&OMNI longer GITs because plant material harder to digest
-Cecum houses symbiotic bacteria and protists that hydrolyze cellulose in non-ruminant herbivores that have longer cecums than carnivores

Front 118

Mutualistic adaptations

Back 118

-SYMBIOTIC BACTERIA
-In cecum of non-ruminant herbivores
-In some birds' crops
-Human large intestine
-Ruminants' stomach

Front 119

COPROPHAGY

Back 119

-Symbiotic bacteria in their cecum and large intestine where they digest, by fermentation, into nutrients
-Unique adaptation for recovering nutrients into blood stream
-Production/excretion of cecal pellets which they then eat and process through GIT until dry
-Ex. rabbits

Front 120

Herbivorous ruminants

Back 120

-Highly specialized 4-chamber stomach
-Stomach's symbiotic bacteria and protists help break down cellulose by fermentation and provide nutrient by-products
-Chewing the cud, regurgitating from first 2 chambers to render plant tissue fibers more accessible to symbiotic microbes
-Methane gas by-product of fermentation (anaerobic hydrolysis) by symbiotic microbes in GITs
-Cattle, deer, sheep, goats, camels, buffalo, llamas

Front 121

Exchange of materials between organism and environment

Back 121

-Must exchange material to survive and reproduce
-@ cellular level
-In unicellular organisms, direct exchange by diffusion

Front 122

Problem w/ diffusion

Back 122

-Diffusion rate proportional to square of distance
-Diffusion rapid only over very small distances
-Direct exchange with enviro not possible for multicellular organisms

Front 123

Evolutionary sol'ns to diffusion problems in multicellular organisms

Back 123

1) Small and/or thin bodies--> direct exchange with surrounding medium (ex. Platyhelminthes, Cnidarians)
2) Internal circulatory systems: transpo of fluid connecting aqueous enviro of cells to organs exchanging gases, absorbing nutrients, and disposing wastes (in most multi-cellular organisms where direct exchange isn't possible)

Front 124

Circulatory system components (3)

Back 124

1) Circulatory fluid (blood or hemolymph)
2) Set of tubes (blood vessels)
3) Muscular pump (heart)

Front 125

Functions of circulatory system (3)

Back 125

-Transpo of respiratory gases, nutrients, metabolic wastes, hormones & heat
-Body defense and wound repair (immunity)
-Hydrostatic skeleton (using tubes with fluid for movement)

Front 126

Open circulatory system

Back 126

-Vessels open into body cavity
-Blood + intercellular fluid = hemolymph
-Exchange of materials between cells and hemolymph
-Hemolymph pumped by heart through vessels into sinuses around organs
-Heart draws hemolymph back into circulatory sys via ostia pores
-Arthropods and molluscs

Front 127

Closed circulatory system

Back 127

-Blood confined in vessels (x mixing with interstitial fluid)
-Vessel hierarchy
-Unidirectional blood flow
-Nutrients and gases diffuse from blood to interstitial fluid bathing the cells and then into cells
-Some invertebrates, all vertebrates

Front 128

Open vs. Closed circulatory system

Back 128

OPEN
-hemolymph
-low fluid pressure
-low fluid circulation speed
-little regulation of fluid flow
-high fluid volume
-low E requirement
CLOSED
-blood
-high fluid pressure
-high fluid circulation speed
-highly regulated fluid flow
-low fluid volume
-high E requirement

Front 129

Types of pumps (3)

Back 129

1) Simple collapsible tube surrounded by muscles (ex. vertebrate skeletal muscle pump)
2) Peristaltic pump, tube has contractile ability (ex. annelids, insects)
3) Chamber pumps, hearts with muscular walls (ex. vertebrates, molluscs)
3)

Front 130

Invertebrate circulation 2 main solutions

Back 130

1) direct diffusion: simple body plan, gastrovascular cavity, cells bather in fluid
2) active transport: many cell layers, circulatory fluid, tubes, pump, open or closed system

Front 131

Vertebrate circulation

Back 131

-Closed cardio-vascular system
-Chambered heart (2-4), atria receive blood entering heart, ventricles pump blood from heart towards organs
-Blood vessels: arteries, veins, capillaries
-Arteries carry O2 blood from heart to organs, send deox blood to lungs/gills
-Veins return blood from tissues to heart, carry O2-rich blood to heart from lungs
-Capillaries microscopic, thin-walled vessels in all tissues, site of diffusion of materials between blood & intercellular fluid
-Single circuit or double circuit of blood circulation

Front 132

Evolutionary trends in vertebrate cardiovascular system

Back 132

-Increased # of heart chambers
-Contractile power of heart increased
-Increased blood pressure
-Single--> double circuit blood flow
-Further separation of ox and deox blood
Increased efficiency of blood flow and diffusion of materials
-Increased complexity
-More active lifestyles and larger body sizes better supported

Front 133

Fish circulation

Back 133

-2-chambered heart (atrium + ventricle)
-Single circuit blood flow, 1 pump
-Blood from ventricle to gill capillaries for gas exchange, gill circulation
-Blood in the systemic capillaries for exchange with cells, systemic circulation
-Blood back to atrium
-High P @ gills, low P @ tissues
-Capillary beds lower blood P--> slow blood flow, facilitates diffusion

Front 134

Double circulation

Back 134

-2 circuits
-Heart with double pump
-O2-poor and O2-rich blood pumped separately from R and L sides of heart
-Higher blood P @ body tissue level
-Amphibians, reptiles, and mammals

Front 135

Amphibians Cardiovascular system

Back 135

-3-chambered heart (2A+V)
-Double circulation (pulmocutaneous and systemic circulation)
-Ventricle ridge partially separates deox and ox blood
-Low blood P compared to birds and mammals
-Underwater, blood flow to lungs nearly shut off, most of blood flows to skin

Front 136

Reptiles (excluding birds) cardiovascular system

Back 136

-3-chambered heart (2A+V) but 4 in crocodilians
-Double circulation, pulmonary + systemic
-Partial septum in ventricle--> less mixing (full septum in crocodiles--> 4 chambers)
-Crocodiles: underwater, blood flow diverted from pulmonary circuit (lungs) to systemic circuit

Front 137

Birds and Mammals Cardiovascular system

Back 137

-4-chambered heart (2A+2V)
-Full septum
-Double circulation, pulmonary and systemic
-High blood P and high blood V and flow rate to tissues
-Endothermy permited (enhanced O2 delivery and removal of wastes, increased E capacity)
-Mammals and birds evolved convgerently

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Cardiac cycle

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-Rhythmic cycle of heart contraction and relaxation
-DIASTOLE: relaxation, blood flows into heart
-SYSTOLE: contraction, blood pumped out of heart
-Lasts 0.8 sec for typical human @ rest, 72 beats/min
-1/2 time in diastole>V sys, A dias>A sys V dias

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Cardiac valves

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-4 valves, flaps of connective tissue
-Prevention of backflow of blood (maintain unidirection), prevent O2-poor & O2-rich mixing
-Defective valves--> heart murmur
-ATRIOVENTRICULAR valves: between A and V
-SEMILUNAR valves: output of V

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Control of heart rhythm

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-Beat generated by cluser of AUTORHYTHMIC CELLS (automatically produce electrical impulses) setting rate and timing of contraction of cardiac muscle cells
-SINOATRIAL NODE (pacemaker): cluster of electrical cells in R-A wall

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Blood vessels: arteries & veins

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-3 layers of tissue
~outer layer: connective tissue with elastic fibers
~middle layer: smooth muscle with elastic fibers
~inner layer: smooth epithelium
~lumen
-Arteries: thick and elastic, under high P, resist and maintain blood P (include capillaries)
-Veins: thinner, under lower P, large veins have valves to prevent backflow

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Capillaries

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-Only have inner endothelial layer
-Facilitates diffusion
-Unidirectional flow through capillary bed
-Beds in brain, heart, kidneys and liver always full with blood (vital organs)
-Blood supply to other tissues vary over time as its diverted from one destination to another

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Blood flow velocity and blood pressure

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-Slowest velocity in capillary beds because of high resistance and large total cross-sectional area
-Necessarily slow in capillaries for exchange
-Blood P is hydrostatic P that blood exerts against vessel wall
-Blood P declines with decreasing rigidity of blood vessels

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Blood pressure

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-Systolic blood P (closer to the heart) > Diastolic blood P

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Exchange of materials in capillary beds

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-Some molecules carried across endothelial membranes in vesicles and released in interstitial fluid
-Small molecules (O2, CO2) diffused into and out of capillaries
-Fluid with solutes moves in and out through clefts between epithelial cells as result of differential pressure between blood P and osmotic P of interstitial fluid
-Differential pressures favour fluid loss from inflow end of capillary and fluid recovery at other end
-Fluid not recovered by capillaries returned to circulatory sys via lymphatic system

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Circulating fluid components

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-Invertebrates hemolymph not different from interstitial fluid
-Blood in closed circulatory systems of vertebrates is a specialized connective tissue
-Vertebrate blood = cells suspended in PLASMA, cellular elements occupy 45% of blood V and have varied specialized functions

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Composition of mammalian blood

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PLASMA
-Water: solvent
-Ions: osmotic balance, pH buffering, regulation of membrane permeability
-Proteins: osmotic balance, pH buffering, clotting, defense
-Substances transported
CELLULAR CMPNTS
-Epythrocytes: red blood cells, O2 and CO2 transpo
-Leukocytes: white blood cells, immunity and defense
-Platelets: blood clotting

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Gas exchange steps (4)

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1) Ventilation: air or water through specialized gas-exchange organs
2) Gas exchange: O2 and CO2 diffuse between air/water and blood @ respiratory surface
3) Circulation: transpo of gases to and from respiratory surface and body cells
4) Cellular respiration: O2 and CO2 diffuse between blood & cells--> ATP

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Respiratory system components

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-Specialized ventilatory structures, carry air or water over gas exchange surfaces (ex. tracheae, operculum of gills, rib cage, diaphragm)
-Specialized respiratory surfaces, large SAs, moist, well vascularized with thin-walled blood vessels (ex. skin, gills, lungs)

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Gas exchange principles

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-Across respiratory surfaces, diffusion
-Brownian motion of molecules
-Fick's law of diffusion:
Rate = [K*SA*(P1-P2)]/D
~K: constant for solubility of gas in aqueous film on exchange surface
~SA: epithelium SA
~(P1-P2): difference in partial pressure of gas across surface
~D: barrier thickness
-Maximization of gas diffusion rate across membranes:
~max differential partial pressure (P1-P2)
~max SA of membranes
~min thickness (D) of membranes
-Small animals: high SA:V, ribbon-like, body surface=gas exchange surface, ex. Porifera, Cnidarians, Platyhelminthes
-Large animals: lower SA:V, most cells far from surface, higher meta rate, specialized gas exchange surface, circulatory sys

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Partial pressure

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-Pressure exerted by a particular gas in a mixture of gases
-Direction and rate of movement depends on relative partial pressure
[P exerted by mixture]*[%of mixture comprising particular gas]
-Gas diffuses from high partial P to low partial P
-[O2] higher in enviro than in cells, tends to move into cells
-[CO2] higher in cells, tends to move to enviro

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Concentration and availability of oxygen in air

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-Relative O2 content remains 21% at all altitudes
-Fewer O2 molecules @ higher altitudes
-Atmsphrc P decreases with increasing alt
-O2 availability decreases with increasing altitude

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Partial pressure of oxygen in air

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-Significant reduction in partial pressure of oxygen @ higher altitudes--> rate of O2 diffusion into body decreases, organisms have physiological adaptations in breathing & blood content to tolerate low [O2]

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Behaviour of oxygen in water

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-O2 solubility in water < in air
-Aquatic animal has to process 30X more water across surfaces than terrestrial for same amnt O2
-Respiration more energetically $$$ in water

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Factors affecting gas diffusion into water

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-Basic solubility of gas, in water lower than in air
-Temperature of water, cold water holds more O2
-Presence of other solutes, sea water holds less O2 than freshwater
-Partial P of gas @ air-water interface, higher atm P increases diffusion from air to water
-SA of water, greater SA--> more diffusion into water
-Turbulence of water surface: increased turbulence--> increased SA--> increased O2 diffusion

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Integument gas exchange system

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-Animal must be small, large SA
-Very thin skin, small D
-Moist enviro
-Ex. salamanders, frogs, earthworms

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Gills in invertebrates gas exchange system

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-Gills: outfoldings of body surface directly in contact with water
-Increase respiratory SA
-Thin epithelium

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Gills in fishes

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-Most specialized and complex of all gills
-Analogous evolution to invertebrate gills
-Water pumped through mouth over gills by coordination of jaws and opercula, bony flap over gills (1-way flow)
-4 gill arches of many filaments and lamellae containing capillary beds
-Countercurrent exchange

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Counter current gas exchange in the lamellae (fish gills)

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-H2O moves opposite to blood flow
-Water flow over lamellae and blood flow inside capillaries
-Difference in partial P remains high over entire lamellar surface
-Rate of gas diffusion across lamellar epithelium maximized
-Partial P of ox in water > Partial P of ox in blood

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Tracheal system of terrestrial arthropods

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-Extensive network of air sacs and branching air tubes
-Tracheae lead from spiracles to interior where tracheoles extend to cell surfaces
-Spiracles close to prevent water loss
-Gas diffusion and/or ventilation
-Completely separate from open circulatory sys

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Lungs, terrestrial gas exchange system

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-Internal site of gas exchange
-Gas exchange membranes inside body to prevent desiccation and protect from damage

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Lung alveoli

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-Dead-end multi-lobed air sacs, make up gas exchange surface of lungs
-150 million alveoli in humans
-Surrounded by blood capillaries
-Thin epithelium
-Total SA related to metabolic rate
-Pulmonary vein carries O2, pulmonary artery carries CO2

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Breathing (ventilation) process in Amphibians, Mammals and Birds

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Amphibians
-Positive P, push air into lungs using floor of mouth
Mammals
-Negative P, pulling in air and pushing out by changing lung V
-Inhalation: diaphragm contracts down, chest expands--> increase V
-Exhalation: diaphragm relaxes, chest contracts--> decrease V
-Bidirectional
Birds
-Lungs + 8-9 air sacs (Xalveoli)
-Unidirectional air flow
-Gas exchange on inhalation and exhalation, fairly high P maintained
-Chest and air sacs don't compress @ same time

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Control of breathing in humans

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-Largely involuntary
-Brain stem= control centre
-@ rest, 10-15 inhalations/min
-Increased during exercise and @ higher alt

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Respiratory pigments and gas transpo

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-B/c of low solubility in blood, O2 needs to be bound to carrier molecule and transpo'd
-Respiratory pigments:
~hemocyanin (molluscs&arthropods)
~hemoglobin (vertebrates and many invertebrates), each molecule carries 4 O2
-Some CO2 carried by pigments but most dissolved in blood plasma