BIO 111 Exam #4

Transport Systems

work via bulk flow to move materials long distances

Respiratory systems

transport O2 into and CO2 out of the animal body

Circulatory system

-internal transport of O2 and nutrients as close as possible to every cell

-collects and transports wastes from every cell to organs systems for removal.

Diffusion

how materials move across cell membranes

Across membranes

exchange happens at the level of the cell here

Down

cells diffuse in what direction of their gradient

Single-celled organisms

have sufficient membrane surface area in contact w/ environment to carry out all necessary exchange via diffusion

Simple Body plans

-gas exchange

-some invertebrates (hydras, jellies, flatworms)

-Gastrovascular cavity placing most cells directly in contact w/ the environment

-Digestion and distribution of nutrients and O2

Complex body plans

-gas exchange

-invertebrates (molluscs, arthropods, earthworms)

-All vertebrates

-Circulatory system

-no function in digestion

Pump

muscular heart(s) that power circulation of fluid through vessels

Vessels

carry fluid around the animal body

Fluid

-blood or hemolymph

-contains respiratory gases, nutrients, hormones, water, etc.

Closed system

-fluid completely contain within vessels (materials diffuse across vessels)

-circulatory fluid does not mix with interstitial fluid

-blood

Open system

-fluid escapes vessels through sinuses and bathes cells with materials they need

-Circulatory fluid mixes with interstitial fluid

-hemolymph

Sinuses

-spaces surrounding the organs where fluid escapes in opened circulatory systems

Intracellular fluid

fluid inside cells

Extracellular fluid (interstitial)

fluid surrounding cells

Blood or hemolymph

inside circulatory vessels

Vertebrates and annelida

what two groups have closed circulatory systems

Opened

-low hydrostatic pressure

-metabolically economical

-less efficient regulation of blood flow to organs, limits to upper body parts

Closed

-high hydrostatic pressure

-metabolically expensive

-very efficient regulation of blood flow to organs

-animals can be larger and more active

Cardiovascular system

the heart and blood vessels in vertebrates

Arteries

-blood flows away from the heart via

Capillaries

-blood flows back to the heart via

-exchanges materials with every cell of the body

Arterial system

moves blood away from the heart and to organs

Arterioles

small vessels that bring blood to capillaries within organs (site or exchange)

Capillaries

microscopic, thin, porous vessels infiltrate tissues as dense networks ("capillaries bed") - pass within a few cell diameters of every cell in the body

Venous system

move blood away from the organs and back to the heart

venules

-within organs

-carry blood from the capillaries to the heart

-converge into veins that carry blood back to the heart

Atria

chambers receiving blood entering the heart (from vein)

Ventricles

chambers pumping blood out of the heart (artery)

Single-circuit system

-one pump

-water-breathing fish (bony & cartilaginous)

-two-chambered heart (one atrium & ventricle)

Double-circuit system

-two pumps

-tetrapods: amphibians, reptiles + birds, mammals

-blood moves around the body in two loops (pulmonary and systemic)

-each loop has own pump combined into one organ

Pulmonary circuit

loop to the lung capillaries to get rid of CO2 and pick up new O2

Systemic Circuit

one to body tissue capillaries to deliver O2 and pick up CO2 waste

Right

side of the heart that powers the pulmonary circuit

Left

side of the heart that powers systemic circuit

Systemic

Circuit with higher blood pressure to overcome resistance of all the body's capillary beds

Ectotherms

-apneustic breathing

-enables circulatory system to temporarily bypass the lungs in part or in whole during breath-hold

Apneustic breathing

intermittent breathers hold their breath for long periods, fill lungs w/ fresh air periodically

Endotherms

-eupneustic breather

-adaptions enable circulatory system to constantly deliver large amounts of oxygen and fuel to tissues (remove CO2 and waster)

Eupneustic breather

continuous breathers but use 10x more energy than equally-sized ectotherms.

Amphibians

-double circulation

-three chambered heart (two atria, one ventricle)

-O2 poor blood fills the right atrium from the body (systemic) then to ventricle

-O2 rich blood simultaneously fills the left atrium from the lungs and skin (pulmocutaneous circuit) to ventricle

-blood mixes bc is not seperated

Spiral Valve

-amphibians

-ridge within ventricle that diverts most O2-rich blood into the systemic circuit and most O2-poor blood to the pulmocutaneous circuit.

-90% effective

Birds & Mammals

-double circuit

-large, powerful four-chambered heart (two atria & two ventricle)

-O2-poor blood fills the right atrium form systemic/body to right ventricle

-O2-rich blood fills the left atrium from the lungs/pulmonary into the left ventricle

-completely separated

Diastole

-relaxation phase

-chamber fills w/ blood

-in between heartbeats

Systole

-contraction phase

-chambers pump blood out

Out of Phase

-atrial and ventricular systoles are...

-prevents ventricle from contracting before the atria have finished (vice versa)

-Allows directionality to blood flow; always forward never backwards

-One-way valves b/w chambers and blood vessels prevent backflow as chambers contract.

Autorhythmic

-heart is self-excitable and sets its own pace

-not controlled by the nervous system

-input form endocrine and nervous system can modify pace, but does not require external controls

Connective tissue

-made mostly of cells suspended in a liquid matrix (plasma)

-connects to all cells indirectly via tiny, porous blood vessels (capillaries)

red blood cells

-specialized hemocytes for transporting O2 (some CO2)

-Found in all vertebrates & some invertebrates

Mammalian RBC

-Tiny

-non-nucleated

-no organelles

-biconcave shape that maximizes surface area for gas exchange

Hemolymph

-plasma mixture that fills body cavity (hemocoel) of some animals

-not contained within the circulatory system

-fluid bathes all cells directly

-open circulatory animals as bulk flow

Ostia

openings where hemolymph re-enters the heart

Water breathers

-expend much more energy to carry out gas exchange

-efficient oxygen extraction from H2O (80%)

Respiratory surfaces

-specialized differently across species depedning on body size, complexity or body plan, & respiratory medium (h2O or air)

-Moist

-Large and thin

Specialized respiratory organs

gills, tracheae, or lungs

Gills

-out-foldings of body surface that are suspended in water.

-can be external to the body (invertebrates) or located inside a protected cavity (fish)

-surface are >>>> total body surface area

Ventilate

-larger animals

-actively move water across their gills

Countercurrent exchange

-maximizes oxygen extraction efficiency

-capillaries arranged relative to the water flow such that there is always a gradient that favors the movement of O2 into the blood

tracheal system

-in air, respiratory surfaces are inflodings with the animal

-most common in insects (arthropods)

Insect Tracheal system

-branched network of tubes that open to the outside, bring air to mitochondria of every body cell

-not coupled with circulatory system

-air-sacs

-no true lungs

Tetrapod Lungs

-air

-respiratory surfaces are inflodings within the animal

-not spread throughout the body- localized respiratory organs

-must be bridged to all body cells via a circulatory system

Cutaneous respiration

- some amphibians

-gas exchange across the skin

-surface area increased by feathery gills, hair-like projections, or highly folded skins

-highly vascularized w/ subcutaneous capillaries to reduce distance b/w incoming air and circulatory system

Conducting zone

-upper respiratory tract

-no gas exchange

-bulk transport, humidification, warming of air

-filtration: mucus and beating cilia trap & remove dust, pollen, pathogens

Respiratory Zone

-lower respiratory tract

-contains alveoli : gas exchange surfaces

Alveoli

-thin-walled membranous sacs

-wrapped with extensive capillary network cover 80-90% surface

-diffusion distance as thin as possible

Negative Pressure

-active ventilation

-sucks air into lungs

-contraction of muscles increases volume creating a vacuum effect

-mammals, non-avian reptiles, insects

Positive Pressure

-active ventilation

-swallow air/water in

-contraction of breathing muscles pushes air into air spaces (h2o across gills), forcing them to expand (blowing up balloon)

-amphibians, fishes (cartilaginous and bony)

Water Fanning

-active ventilation

-rare

-moving gills through water

-axolotl, marine polychaete worms

Passive Ventilation

-slow-moving or sedentary, small-bodied animals with a simple body plan do not necessarily need to actively ventilate

-allowing medium to move across respiratory surface is sufficient

-Many aquatic species (echinoderms, cnidarians, porifera)

Respiratory pigements

-O2 transported bound to proteins

-oxygen sink

-greatly increase O2-carrying capacity

-pulls O2 out of blood (not soluble)

-maintains gradient (favors movement into body)

-transport CO2 away from active tissues

Neural Circuit

pathway of information transfer between individual, interconnected neurons

Nervous system

neural circuits together with supporting cells

Radial bodies

-hydras and other cnidarians

-simplest animals w/ NVS

-nerve net (controls gastrovascular contraction and expansion)

Cephalization

-cluster of interneurons at the anterior(front) end of the body that carry out integration (CNS)

-includes a brain and clustering of sensory neurons

-in planarians and other non-segmented worms, a small brain and longitudinal nerve cords form the simplest clearly defined CNS among animals.

Nerves

-neuron axon bundled together into fibrous channels that organize information flow around the body- a peripheral nervous system

-Carry information toward and away from CNS

Ventral Nerve Cord

-"along the underside"

-coordinates neural signaling between brain and body in both directions

-contain ganglia

-functional equivalent to dorsal spinal cord in vertebrates

-major structure of the insect nervous system

Ganglia

clusters of neurons that serve as relay points in information transfer

Spinal cord

-aka dorsal nerve cord

-"along the backside"

-coordinates neural signaling between brain and body in both directions

-Contains sensory ganglia

-brain + spinal = CNS

-nerves + ganglia = PNS

Peripheral nervous system

paired nerves that transmit information toward and away from the CNS

Central nervous system

brain and spinal cord

Afferent

-sensory information reaches CNS along these PNS neurons

-to CNS

Efferent

-following info. processing by the CNS, instructions travel to effectors along these PNS neurons

-Away from CNS

Somatic motor and autonomic

The two divisions of the PNS

somatic Motor system

-regulation of skeletal muscles ONLY

-"voluntary" (plus reflexes)

Autonomic system

-regulation of cardiac and smooth muscle

-"involuntary"

-Split into three subdivisions: sympathetic, parasympathetic, and enteric systems

Sympathetic neurons

-promote a state of hyperarousal

-"fight or flight"

-heart beats faster, digestion slows

Parasympathetic neurons

-promote a state of calming and self-maintenance

-"rest and digest"

-heart beat slows, digestion upregulated, and pupils constrict, etc.

Enteric nerurons

-neurons carry signals to smooth muscles to regulate organs of the digestive system only

-division is its own distinct network of neurons

-Can act independent of input from any other component of the vertebrate nervous system

-interacts w/ the autonomic NS to regulate digestion when appropriate

-"gut brain" or "second brain"

-evolved first

Brain

-most complex organ in the vertebrate body

-regionally specialized

-three main regions

Hindbrain

-reflex response

-homeostatic functions

Midbrain

-sensory routing & integrating center

-makes decisions from all the info. it receives

Forebrain

-integration center

-learning, memory, emotions

-complex processing tasks

-large surface area

cerebrum

-aka forebrain

Cerebral cortex

-most outer layer made up of clusters of neural cell bodies (gray matter)

-controls voluntary movement and cognitive functions

-Sensory area, association area, and motor area

sensory areas

receives and processes sensory information from afferent neurons (ex: visual cortex)

association areas

integrate that sensory info. and makes decisions using interneurons (prefrontal cortex)

Motor areas

transmits instructions to other parts of the body via efferent neurons (motor cortex)

Four steps to sensation

1. sensory reception

2. sensory transduction

3. sensory transmission

4. sensory perception