hydrostatic skeleton

examples

muscles enclose sacs of fluid

worms, insect larvae, many mollusks

exoskeleton

examples

external to body tissues, forms body surface

arthropod

endoskeleton

examples

internal to some body tissues, mineralized

echinoderms (starfish) and vertebrates

bone:

cells in mature bone are osteocytes

highly mineralized matrix

vascularized

cartilage:

cells are chondrocytes

firm, gelatinous matrix

vascularized

______________ bind to actin

_____ _____ move, pulling on _____, toward center of _____

_____ filaments slide over _____ filaments --> muscle _____

does filament length change?

myosin cross-bridges bind to actin

myosin heads move, pulling on actin, toward center of sarcomere

thin filaments slide over thick filaments --> muscle contracts

filament length does not change, but sarcomere shortens

1. energized myosin cross-bridge, with ADO and Pi, binds to actin
2. Pi released, cross bridge moves and actin slides; ADP released
3. ATP binds to myosin, cross-bridge detaches
4. ATP hydrolysis resets cross-bridge

1. ATP hydrolysis resets myosin head
2. ATP binding to myosin after power stroke detaches cross-bridge from actin

contraction is regulated with Ca²⁺

tropomyosin

troponin

tropomyosin:
long proteins

cover myosin-binding site to actin

troponin:

small proteins

bound to tropomyosin and actin

troponin

binds to _____

pulls _____, away from _____ myosin-binding site

_____ begins

remove _____; process _____; contraction _____

binds to Ca²⁺

pulls tropomyosin, away from actin's myosin-binding site

contraction begins

remove Ca²⁺; process reverses; contraction stops

1. action potentials are propagated through t-tububles
2. Ca channels open in response to depolarization
3. Ca binds to troponin
4. troponin changes conformation, etc., muscle contracts
5. Ca is returned to sarcoplasmic reticulum by Ca pumps
6. Low intracellular lelvels of Ca stops muscle contraction

resting muscles: very low...

______ wraps around each myofibril

t-tubules: (2)

very low cytoplasmic lelvels of Ca

modified endoplasmic reticulum wraps around each myofibril

channels of plasma membrane, associated with SR

conduction action potentials from outer surface of muscle fiber to inner region

1. gastrovascular cavities
2. open systems
3. closed systems

gastrovascular cavities (_____)

# of openings of body cavity to environment?

# body cavities for digestion and waste excretion?

_______ move fluid through cavity

gastrovascular cavities (cnidarians)

1 opening of body cavity to environment?

1 body cavity for digestion and waste excretion?

body contractions move fluid through cavity

open circulatory systems

contain _____ (=analogous to _____ in open circulatory system)

vessels open into ________; _____ mixes with _____

one or more _____

exchange at cellular level by _______

energetically expensive or inexpensive?

open circulatory systems

contain hemolymph (=analogous to blood in open circulatory system)

vessels open into body cavity; hemolymph mixes with interstitial fluid

one or more hearts

exchange at cellular level by diffusion

energetically inexpensive

closed circulatory systems (_______ _______ _______)

energetically expensive or inexpensive?

contain _____

is pumped by 1 or more _____

moves through in _____

_____ and _____ from interstitial fluid

closed circulatory systems (earthworms, cephalopods, all vertebrates)

energetically expensive

contain blood

is pumped by 1 or more hearts

moves through in tubes

separate and different from interstitial fluid

"double circulation"

_____ and mammals

_____ and _____ blood separated

2 parallel ______

2 ____ and 2 _____

major advantage:

"double circulation"

birds and mammals

oxygenated and deoxygenated blood separated

2 parallel circuits: systemic and pulmonary

2 atria and 2 ventricles

major advantage: systems run on different pressures

vertebrate hearts are _____ (=controls its own heart beat)

modified cardiac muscle cells at the _________ (_____) generate an action potential

signal spreads through ___________ (electrically coupled)

____________ input increases or decreases rate

vertebrate hearts are myogenetic (=controls its own heart beat)

modified cardiac muscle cells at the sinoatrial node (pacemaker) generate an action potential

signal spreads through cardiac muscle cells (electrically coupled)

nervous system input increases or decreases rate

cardiac muscle cells connected by _________ (protein to protein connections that allow ions and small molecules to move between cells)

_______ spreads efficiently through cardiac tissue

cardiac muscle cells connected by gap junctions (protein to protein connections that allow ions and small molecules to move between cells)

depolarization spreads efficiently through cardiac tissue

diastole

systole

_____ carry blood away from heart

thick or thin walls?

valves: yes or no?

lots or little smooth and elastic connective tissue?

arteries carry blood away from heart

thick walls

valves: no

lots of smooth and elastic connective tissue

_____ carry blood toward heart

thick or thin walls?

valves: yes or no?

lots or little smooth and elastic connective tissue?

veins carry blood toward heart

thin walls

valves: yes (some)

little smooth and elastic connective tissue

capillaries are a _____ layer of cells on a _____ _____

site of _____ and _____/_____ exchange

blood enters capillary on _____ end under pressure; forces fluid out of capillary and into _____ _____

_____ force of the blood proteins then draws fluid back into capillary

_____ system collects any leftover ____ and return it to the _____

pressure=_____ ; osmotic=_____

capillaries are a single layer of cells on a basement membrane

site of gas and nutrient/waste exchange

blood enters capillary on arteriole end under pressure; forces fluid out of capillary and into interstitial space

osmotic force of the blood proteins then draws fluid back into capillary

lymphatic system collects any leftover fluid and return it to the blood

pressure=arteriole ; osmotic=venule

plasma

%?

consists of ____ and _____

3 jobs

35-60%

consists of water and solutes

buffering, water balance and cell transport

leukocytes (aka _____)

job?

leukocytes (aka white blood cells)

immune system

erythrocytes (aka _____)

%?

job?

erythrocytes (aka red blood cells)

40-65%

transport oxygen

platelets

job?

21% oxygen

78% nitrogen

<1% other

pressure equation

units?

this pressure drives _____ of the gas across a ______ surface

pressure = force/area

mmHg

this pressure drives diffusion of the gas across a respiratory surface

___x more dense than air

___ the amount of oxygen, depending on: (3)

~800x more dense than air

1/30 the amount of oxygen, depending on:

water temperature

pressure

presence of other solutes

bulk flow

diffusion

F = KA(C₁-C₂)

F=flux

K=coefficient

A=surface area

C₁=concentration on one side of membrane

C₂= concentration on other side of membrane