Exam 3

Anatomy

Structure of an organism’s body

Physiology

Function of cells, tissues, and organs

Radial symmetry

Plane cut along longitudinal axis produces equal halves but no definite left and right side, mostly aquatic animals

Bilateral symmetry

Plane cut from front to back separates animal into left and right sides, enables mobility

Anterior

Front

Posterior

Rear

Dorsal

Toward back

Ventral

Toward stomach

Fusiform

Tubular shaped body that is tapered at both ends, decreases drag on the body and increases swimming speed

Apodemes

Ingrowths of exoskeleton, attachment sites for muscles

Endotherms

Warm-blooded animal, retains relatively stable body temp by conserving heat, basal metabolic rate which requires more energy, production and regulation of metabolic heat allows constant internal temp, metabolic heat production increases in cold environment

Ectotherms

Cold-blooded, absence of insulation so depends on environment for body heat, standard metabolic rate, reptiles, fish, invertebrates, metabolic heat production decreases in cold environment, linear relationship with environmental temperature, exponential relationship between metabolic rate and environmental temp, as they get warmer metabolism becomes more active

Torpor

Process that leads to decrease in activity and metabolism, allows animals to survive adverse conditions, hibernation in winter and estivation in summer

Sagittal plane

Right and left

Midsagittal plane

Exactly in middle

Frontal plane

Front and back

Transverse plane

Upper and lower

Dorsal cavity

Contains cranial and vertebral cavities

Ventral cavity

Thoracic cavity, pleural cavity around lungs, pericardial cavity surrounds heat, abdominopelvic cavity

Homeostasis

Seeks to maintain dynamic equilibrium in the body, adjusting to changes body systems encounter

Set point

Point or value homeostasis seeks to maintain, adjustible, lower when skin is warm and raised when skin is cold

Negative feedback loop

Any homeostasis process that changes direction of stimulus, can increase or decrease stimulus, returns physiological state back to a set point after it changes, organism will cease to produce additional molecule A once enough molecule B has been produced, ending overall response

Positive feedback loop

Maintains direction of stimulus, possibly accelerating it, blood clotting, reinforces a change to physiological state to accelerate that change, production of molecule B stimulates further production of molecule A which proudces more of molecule B, enhancing overall response

Alteration of set point

Feedback loop works to maintain new setting, sees new set point as normal and makes no attempt to change it

Acclimatization

Changes can be made in a group of body organ systems to maintain set point in another system

Thermoregulation

Temperature control, centered in hypothalamus of animal brain

Surface area to volume ratio

as sphere’s diameter increases, ratio decreases, bigger object should have smaller ratio, largest ratio for things with folds and wrinkles

Shape of organism

Impacts efficiency of diffusion

Temperature of organism

Heat exchange depends on ratio

Surface area

Total exterior area of 3D molecule, more allows for more space for transmembrane proteins to pass things in and out and faster diffusion of cell membrane

Volume

Amount of space an object occupies

Optimization of surface area to volume ratio

Single large cell has small ratio that reduces efficiency of solute transport in and out of cell, cells are small and have villi to increase ratio

Diffusion

Spontaneous movement of matter, area of higher concentration to lower concentration, leading to state of equilibrium

Time it takes to reach equilibrium

Depends on size/mass of molecule, temperature of system, density of solution, steepness of concentration gradient, and area over which diffusion occurs

Gas exchange

Occurs by diffusion across cell membranes, does not require energy

Negative feedback controls body temp

Hypothalamus receives information from the body to determine current temp, with respect to desired set point, body takes actions to return body to optimal body temp

Positive feedback stimulates blood clotting

Injury to wall of a blood vessel releases signaling molecules that recruits platelets to site of injury, recruited platelets adhere to site and release their own signals that cause more platelets to arrive, once clot has sealed injury and filorin protein network has stabilized repair loop is broken through negative feedback

Biological processes depend on temperature

reaction rate increases at higher temp, sufficiently high temps can denature proteins, biological membrane fluidity increases with increasing temperature, enzymes have optimal temperature range,

Heterothermy

Groundhog, adopt endothermic and ectothermic regulatory strategies at different times, such as during hibernation, can only control body temperature sometimes

Metabolic rate

Amount of energy an organism is currently spending

Below lower critcal temperature

Endotherms expend energy to to produce metabolic heat

Abover upper critical temp

Endotherm expends energy to lose heat by panting or sweating

Energy expenditure at low temperatures

Proportional to the difference between body temp and environmental temp, upper limit of survival is based on denaturation of proteins and destabilization of lipid membranes

Thermoneutral zone

environmental temp matches homeostatic temp so endothermic metabolic activity is minimized, body temp is regulated by low energetic cost mechanisms, such as changes in blood flow to skin and changes in posture, narrow because organisms usually expend energy beyond basal metabolic rate, linear decrease from 0 to TNZ then linear increase after TNZ

Countercurrent exchange

Efficiently manages temperature or respiration, deoxygenated blood and water flow unidirectionally in opposite directions, gradient of oxygen saturation exists over full length of exchange surfaces, exchange is more complete, water out higher than water in, in gills high concentration of oxygen from water comes in, goes over gills, gills go from low to high oxygen concentration as it goes back to body’s circulation, blood is oxygenated over process

Regional heterothermy

Maintaining core temp and allowing extremities to cool to near freezing, due to temperature difference heat will transfer to veins, cold blood returns from feet but is warmed on the way back by countercurrent exchange, uses much less energy

CO2 diffusion

Primarily transported in blood as HCO3 ions, 5% diffuses from cells into blood plasma into red blood cells, 20% combines with hemoglobin, 70% is rapidly converted into bicarbonate ions catalyzed by carbonic acid

Bicarbonate ions

Enter blood plasma in exchange for chloride ions, in lungs processes are reversed

Bicarbonate ions in lungs

forms carbonic acid which dissociates releasing CO2, diffuses out of red blood cells to blood plasma and to air in alveolus and exhaled

Hemoglobin

Reversibly binds oxygen, irreversible binding would prevent gas exchange, binding is determined by oxygen partial pressure, follows sigmoidal relationship, saturation reaches high level at intermediate partial pressure, protein in red blood cells made of alpha and beta subuits, has central heme group that contains iron and binds oxygen

Sigmoidal curve

Steep slope indicates that loading and unloading is very efficient at lower partial pressure, with each binding event shape of hemoglobin complex changes, second and third events are most favorable, fourth oxygen is hard to acquire because it has to find open binding site

Positive cooperativity

From 20-45% partial pressure, there is quick acquisition of oxygen molecules, at 75% most hemoglobin will have 3 oxygens bound and some will have 4

Bohr effect

Rightward shift in hemoglobin’s affinity for oxygen at low pH, can be caused by high levels of CO2, such as high respiration rate, affinity of hemoglobin for oxygen goes down when pH is low to facilitate faster unloading of oxygen to deoxygenated tissues and binding of H+ ions to deoxygenated hemoglobin prevents oxygen from binding

Oxygen affinity

Lowest partial pressure with highest saturation is highest affinity

Myoglobin

Delivers oxygen to oxygen-starved muscles, high oxygen affinity

Fetal hemoglobin

Gets oxygen from adult hemoglobin

Water

Diffuses across semipermeable membrane, moves in/out of cell through osmosis, down concentration gradient to regulate solute concentrations

Tonicity

Attribute describing effect of solution on a cell

Hypertonic

Concentrated solutes outside, animal cells lose water and shrivel, plant cells shrink pulling plasma membrane away from cell wall, water moves out of cell

Isotonic

Equivalent solute concentration, rates of water movement in and out are equal

Hypotonic

Dilute solutes outside, inside of cell has more solute, water moves into cell, animal cell takes up water swells and bursts, plant cell stiffens but maintains shape because of cell wall

Extracellular/interstitial fluid

Lower concentration of K, higher concentration of Na, lower concentration of suspended proteins, transport medium, no reserves stored, masses of insoluble materials

Small multicellular organisms

Diffusion across outer membrane sufficient to meet oxygen needs, cells are kept moist and gases diffuse quickly via direct diffusion

Gills

Thin tissue filaments that house lamellae and are highly branched and folded, take up dissolved oxygen from water, folded surfaces increase surface area, supported by arches that are made up of filaments

Tracheal system

Network of small tubes that carry oxygen to entire body, insect respiratory system

Mammals

Air enters through nasal cavity, passes through pharynx, laryns, and trachea to lungs

Sickle cell anemia

Crescent-shaped red blood cells reduce ability to deliver oxygen

Thalessemia

Rare genetic disease caused by defect in subunit of hemoglobin, reducing oxygen carrying capacity

Superior vena cava

Drains blood from jugular vein and sends deoxygenated blood to right atrium

Inferior vena cava

Drains blood from veins from lower organs and legs, sends to superior vena cava

Triscuspid valve

Opens only in 1 direction to prevent backflow of blood into right ventricle

Semilunar valve

Where right ventricle pumps blood to pulmonary arteries and onto lungs

Biscuspid valve

Where oxygen-rich blood from left atrium passes on the way to aorta

Cardiac cycle

Filling and emptying of the heart of blood by electrical signals that cause muscles to contract and relax

Arteries

Take blood away from the heart

Capillary

Fit red blood cells single file and are sites for nutrient, waste, and oxygen exchange

Veins

Blood vessels that bring blood back to the heart

Fick’s Law D

may change with aquatic vs terrestrial, hot or cold temp, or identity of gas diffusing, diffusion coefficient, combined property of diffusing gas, medium of diffusion and temp of the system

Fick’s Law A

Cross-sectional surface area for gas exchange, may change with temp and lung disease, directly proportional to Q

Fick’s Law P1-P2

Partial pressure difference driving diffusion, steep gradient maintained through active movement of gases and blood

Fick’s Law L

Diffusion path length, directly proportional to Q, reduced through active movement of gases and blood, gases moving through respiratory and circulatory system are carried close to their target and never have to diffuse very far

Ventilation

Maintenance of pressure gradient, moves respiratory medium over gas exchange surfaces

Perfusion

Maintenance of pressure gradient, circulation of blood into, over, and away from gas exchange surfaces

Alveoli

Pockets that make up internal structure of lungs, inside air is very close to blood flowing through networks of capillaries surrounding alveoli, alveolar walls and capillary walls are extremely thin, minimizing distance oxygen must diffuse

Fick’s Law Q

Rate of diffusion/exchange for a gas between points 1 and 2

Respiratory media

Air and water, air is more concentrated in oxygen, less dense, less viscous, air is easier to breathe in

Fish perfusion

arches contain blood vessels that bring in deoxygenated blood and send oxygenated blood to the rest of the body

Fish ventilation

Pump oxygenated water unidirectionally into the mouth and through the gills, then back out

Lamellae

Site of gas exchange in fish gills, provide enormous surface area for gas exchange and are very thin to minimize path length, each performs countercurrent flow, creates pressure gradient that is always maintained to exchange gas or heat

Countercurrent flow gills

water with high oxygen levels ventilates gills, oxygen diffuses from water into blood over length of lamella, blood perfusion of lamellae is countercurrent to flow of water over lamellae, water with low oxygen levels enters the gills while water leaves, concentration gradient favors movement of gas or solute in direction we need it to go

Concurrent flow

Less efficient, will reach equilibrium before oxygen saturation reaches 100% which will stop net movement

Tidal ventilation

Terrestrial animals use lungs to perform gas exchange, inhaled air travels into trachea, then bronchi and bronchioles before reaching alveoli, where gas exchange occurs, no countercurrent exchange

Respiratory tract

Lined with mucus which traps microbes/debris and surfectant which reduces work of breathing

Emphysema

Lung disease characterized by enlargement and breakdown of alveolar structure and reduction of lung elasticity, causes include smoking, air pollution, HIV, genetics, increases volume and reduces surface area leading to reduced air movement and less surfectant

V/Q

Ventilation perfusion ratio, measures respiratory efficiency, diagnostically helpful for understanding different types of respiratory failure, average across all alveoli, V and Q should be similar

Shunt perfusion

Perfusion without ventilation, wasted perfusion, airway obstruction or pneumonia, low V/Q

Normal V/Q

Pefusion and ventilation, gas exchange between capillary and alveoli and blood oxygenation, 0.8

Dead space ventilation

Ventilation without perfusion, wasted ventilation, pulmonary embolism, cardiogenic shock, high V/Q

4 chambered heart

Pulmonary and systemic circuits are totally separate, good for endotherms that do a lot of activity

3 chambered heart

Reduce the amount of oxygen carried but allows more control of where oxygen goes