BIOL 371 Theme 4 Animals

What is homeostasis?

The maintenance of a stable itnernal environment that is SUITBALE for metabolic processess.

Why is homeostasis important (in regards to biochemical processess?)

Biochemical processess only fucntion as specific temp, ph, [solute], [water], and pressures. Therefore, ogranisms must regulate the internal variables in response to external situations.

What are the 8 things organisms must regulate internally?

Nutrients, gasses, ph, waste products, [water/solutes], volume (of fluid), pressure and temp.

How are the internal variables regulated (in general)?

Feedback mechanisms

Describe a negative feedback loop. What are the 7 steps with dog example?

Maintain homeostasis by regulating different variable with reference to a set point (integrator)

1. Change in internal/external environment causes a change in physiological variable (activity on hot day causes rise in body temp)

2. Change is detected by specialized cells (temp is detected by temp sensitive cells on skin)

3. Information is sent to an afferent (sensory) pathway

4. Specialized cells (integrator) recieve the sesnory info and determine what to do (the neuros in the hypthalamus recieve info and determine what to do)

5. Information is sent along the efferent (motor) pathway

6. A system prodcue compensatory changes in the physiological variable affected by environemntal change (panting is produced to cool the body)

7. The actions of the effector return conditions to set point.

Why can cell location have implications on homeostasis?

If a cell is external (skin cells) they must face the enviornment directly.

Therefore, the superficial layers are sometimes dead and may be protected by an acellular (nonliving) cuticle.

What is a requirment of cells surfaces if they control acsess to internal environment?

Must be living to control acsess to itnernal environment.

Cells of exhange surfaces are found (inside/outside) of the body, but must deal with external enviornment. (how?)

Found inside the body.

Anything that is brought from outside the body via a membrane must be regulated by the internal cells.

What 3 things must internal cells of exchange have to deal with wear and tear?

1. Rapid turnover

2. Produce lethal environment to microbes

3. Covered by a secreation (mucus) to isolate them from the environment (so they dont directly interact with it)

How to internal cells do homeostasis?

They only regulate their internal environment, not the external one.

They are NOT isoosmotic with the external environemnt which reduces the amount of work they have to do.

This allows them to specialize.

What are the four types of homeostasis topics?

1. Osmoregulation: regulaton of internal osmotic (water, salt and waste) environment

2. Circulation: Bulk folow of fluid within body needs to be regulated

3. Gas Exchange: With the enviornment, must regulate

4. PH Regulation: must control the [H+] concentration of body (enzymes only work at specific pHs)

What are the three concepts of osmoregulation? What is water potential?

1. Diffusion: SHORT distances, for dissolved soluted *Fickles Law

2. Osmosis and Water Potential: Osmotic potential vs pressure (water potential is the tendency of water)

3. Bulk flow: mass movement over LONG DISTANCES due to mechanical/hydrostatic pressue

What are the things that can affect water potential?

Osmosis, hydrostatic pressure, gravity and humidity

What is diffusion? What is the result?

The tendency of molecules (solutes) to move DOWN a concentratin gradient.

To move from a volume where the [solute] is high, to one that is low.

The dimminuation of a concentration gradient because they do it to find EQUILIBRIUM.

What is Fick's Law? What are the components?

The diffusion rate across a membrane=DA dC/dX D - difusion contant (depents on solute/solvent characters)

A- surface area of membrane

dC- concentration difference across the membrane

dX- thickness of membrane

What is the driving force of diffusion? What does the quantity of particles depend on?

dC/dX (concentration difference/thickness of membrane) - Driving force

The quantity depents on the surface area of the membrane (more SA= more particles move)

What is omsolality?

The osmotic concentration of a solution (measured in osmoles)

What is an osmole?

Total number of dissolved particales of solute/ kg of solvent

If I had 1 mole of NaCl and dissolved it in 1kg water, what is the result?

2 moles of particals - 1 mol of Na and 1mol of Cl

What is hypoosmotic? (water and blood)

A solution having lower (HYPO) osmolality [solute] than the reference solution.

Pure water is hypoosmotic [low solute] compared to the red blood cell [high solute].

Water travels into blood cell, bloats.

What is hyperosmotic? (saline and blood)

A solution has higher (HYPER) osmolality [solute] than the refernce solution.

Strong saline has higher omsolality [high solute] than the blood cell [low solute].

Water travels from blood to saline (shrivles)

What is isoosmotic? (physiological saline and blood)

A solution has the same (ISO) osmolality [solute] as a refernce solution.

A physioloigical saline solution is isoosmotic [same solute] as a red blood cell.

Net movement in and out of cell is same.

What is osmosis? Why important?

The tendency of water DIFFUSE across a selectivley permeable membrane to the side with [high solute] when the membrane is impermeable to solute.

Can regulate the [soltute] without the movment of solutes across a membrane. If [high solute], that means it is [low water], therefore, water moves towards it.

What is osmotic potential? What is it called in plants?

Osmotic potential is the forces extered on water caused by differences in [solute] across semi-permeable membrane (water potential)

What has the highest osmotic potential, what does that mean?

PURE water has the highest osmotic potential (ZERO).

The lower osmotic potential is more negative (higher [solute])

Water moves from less negative [low solute] to more negative [high solute]

**remember low solute means higher water. (high to low water)

What is pressure potential?

The hydrostatic/mechanical oressue that affects how water crosses membrane from high ostomostic potential [low solute] to low osmotic potential [high solute].

Moves up a water concentration gradient.

What is the relationship between pressue potential and osmotic potential?

Pressure potential is opposed to LOW osmotic potential [high solute/low water] - Flow of water across membrane descreases/stops

What is water potential? How does water move?

The SUM of osmotic potential and pressue potential across a membrane.

Water mores from volumes of high water potential [high water], to volume of low water potential [low volume].

Why is osmosis improtant in living ANIMAL cells? An example of cell in fresh water.

If cells are NOT in an isoosmotic environemnt [solute same inside and outside], the cells with shrink or swell (burst).

If cell is in fresh water (high osmotic potential-lots water/low solute), the water will move into the cell [low water/high solute] and the cell will burst. Water follows salt, hence water going into cell with high solute/salt content.

Improtance of osmosis in living PLANT cells?

Plants want to be turgid/develop turgid pressue (high flow water into cells).

The cell wall prevents the cell from bursting by preventing too much water in.

Therfore, when plant cells are in fresh water, the [solute] is higher in cell, therfore, the water moves into plant cell until turgid.

Cell wall prevents further influx of water.

How do capilleries work in animals (bulk flow)?

Pressue potential is added on to blood in the capillery (more pressue, lower volume).

This exceeds the osmotic potential (water concentration) of the extracelllar fluid (pressure potential osmotic potential).

Therefore, the water and solutes LEAVE the capilleries, to a place with a lower volume/less pressure.

**remember pressure potential counter osmotic potential.

Water likes to go from high water (high osmotic potential) to low water (low omsotic potential). If you increase the pressue on a low osmotic potential volume, the volume decrease, and water will flow out (against gradient).

The osmotic potential (water concentration) of the blood downstream exceeds the hydrostatic/pressue potential of the extracellular fluid.

The osmotic potential of the capillery is higher than the pressue potential of the ECF, therfore, the water and solutes move INTO the cappilerry.

What is an osmoconformer?

Asjust osmotic potential (Y) iof cells and extra cellular fluid (X) to MATCH THE ENVIRONMENT.

What is an osmoregulator?

Adjust osmotic potenail of extracellular fluid (X) to match cells (Y) and regulate to protect ECF (X) AGAINST THE EXTERNAL (Z).

Requires thick outer layer to control flow of solute/water in and out

Terrestrial animals and water loss:

[water] inside cell is higher than [water] in environment. Water moves from [high to low]. Net movement out of cell :(

Aquatic animals and water loss/gain:

Marine animals (water loss)[salt/solute] high in environment, [water high/solute low] inside cell. 

Salt moves into the cell, and water moves out of cell (to high solute/low water) area (hyperosmotic -WATER FOLLOWS SALT) 

What type of regulators are better in fresh water?

Osmoregulators- protect the cell against enviornemnt (to not let influx of water in bursting the cell)

Describe the tonicity and regulation of MARINE BONY FISH.

They are hypoosmotic (less solute) to environment and therfore loose water and gain salts (through gills). GAIN SALT LOOSE WATER To offset water loss, they drink sea water [high salt]. To offset salt gain, they have chloride cells in gills to eliminate ions (Na+, K+ and Cl- from blood). - transmembrane pumps use ATP to push ions out of cell against concentration gradient. They produce small amount of urine (to offset water loss) and eliminate solute in feces.

Describe tonicity and regulation of FRESHWATER bony fish.

They are hyperosmotic [high solute] to the enviornment [low solute]. Therefore, water flows INTO THE FISH, and they loose ions to environment through gills. They get plenty of water through gills, therfore, they DO NOT DRINK WATER. To counter amount of water they get, they produce a large amount of dilute urine, to reclaime lost ions. Replenish ions from food or transport across gill membrane.

Describe the tonicity and regulation of elasmobranchs:

They are isoomsotic [same solute] as their enviornment (sea water).

[Na+, K+, Cl-] are less than sea water, so the difference is made up through urea.

They maintain a [high urea] in extracellular fluid. They still get an influx of diffusion of Na+, K+ and Cl- through gills so they regulation that through rectal glands which secrete high concentration solution.

Describe the water loss of terrestrial animals and the requirnments

They have constant water loss through evaporation- across wet respiratory membrane (lungs are wet, whenever we breath we loose water), and across skin surface (sweating).

They also loose water through urine and feces.

Must have waterproofing of out layer and minimal exposure of has exchange and disgetsive surfaces to air.

Terrestrial enironemnts are dry....

LOOSE WATER TO ENVIRONEMT Must consume, produce or converve water and limit salt intake.

Marine enviornments are....hypo/hyperosmotic...

They are HYPEROSMOTIC [high salt]

Therfore, organisms loose water and gain salt from enviornment.

Must eliminate salt intake and consume/produce/consverse water.

Freshwater environment are hyper/hypoosmotic...

They are HYPOOSMOTIC [low salt].

So they GAIN WATER AND LOOSE SALT TO ENVIORNMENT

Elimintate water intake and consume/conserve salt.

How do animals activley regulate water loss and gain? What are the three types of means of waste removal?

Through excretion - eliminates waste and toxins.(aids in controlling the content of extracellular fluid)In marine animals, diffusion of solutes into water by the excretory tubule (liquid waste)

1. Filtration- non selective

2. Secreation - selective

3. Reabsorbtion - selective

What is the excretory tubule made of? What does this allow?

Made up of epithelium which allows ACTIVE transport of ions between the ECF and the filtrate.

Other solute and water diffuse in both directions.

What is important about the permeability of the excretory tubule?

Different permeabilities along different parts of the tubule allows the body to absorb water or loose when needed.

How do aquatic animals get ride of ammonia (NH3)?

1. Diffusion- into the environment by gills/across body

2. Excrete in filrate/urine

3. Ammonium (NH4+) and sodium exchangers

How do terrestrial animals get rid of ammonia (NH3)?

Exctrete through filtrateMammals/ amphibians and sharks produce urea

Snals/ insects and reptiles/birds produce uric acid

**important for animals that develop in an egg

What is a protonephridium?

Rememeber - nephr...means kidney- think excretion

They are filters (with cilia) that filter extracellular fluid to eliminate waste by making a current (cilia).

Drains into a duct where reabsorbtion takes place.

What is metanephridium?

Rememer- nephr...means kidney- think extrection Filters coelomic fluid, and reabsobs it into the circulatory system through blood vessels.

Closed circulatory system

What are malpighian tubules?

It is a large absorbtive surface that is in contact with the naemoymph (circulatory fluid).

Active secretion of uric acid into tubule.

Therfore, water follows (osmosis).

Filtrate is released into gut, and Na+/K+ are activley transported out.

Water follows.

SOLID uric acid is released through feces.

What is the nephron?

Found in vertebrates 

Filters water and solutes from blood and reasbsorbs water and solutes to produce CONCENTRATED urine

Why is it important to circulate fluids?

1. Processing- regulate pH, osmolality, waste, to add nutrient and agas exchange

2. Transportantion/Communication- hormones, heat, nutrients, immune suport and solutes

How to plants and animals differ in circulation?

Nutrient, energy and water sources

Metabolic rates

Cell strucutre Prescence/Absense of a muslce - to pump fluids

What are the two type of circulatory systems?

1. Open- circulatory fluid NOT confined to vessels

2. Closed- circulatory fluid CONFINED to vessels

What are requirments for circulatory systems in animals?

They are heterotrophs with extraceullular digestion, so they have high metabolic rates (demand rapid circulation)

They also have tissues which require - oxygen, nutrients and respiorty wastes (to be removed)

Animals have to move, so vessels must be flexible

How are fluid forced through vessels in animals (circulation)?

They have a muscular pump (heart) that pushed blood through felixbile vasculature.

Describe a open circulatory system: (who is it suitable for, where does the heat sit, contraction/relaxation ect..)

For low pressue and slow fluid movment. Suitable for taxa with SLOW metabolic rates They have a hemolymph which transport fluid in open circulatory systems.

It comes into DIRECT contact with the tissues to form the EXTRACEULLULAR FLUID POOL

The heart sits in the haemolymph filled haemocoes

-Contraction: haemolymph explelled from heart by artieres to other haemolymph filled spaces

-Relaxation: haemolymph enters heart from haemocoel

Valves/ostia in heart maintan the unidirectional flow - when heart contract, the ostia close and force blood out and into arteries (not able to have directed flow to active tissues)

Descibre a closed circulatory system: (where are they found,

Blood is kept under constant varying pressue, where blood vessels and the heart form a CONTINUOUS closed circuit (blood doesnt leak) Found in forms able to sustained HIGH METABOLIC ACTIVITY (such as- annelds, cephlopods, some crustaceons and ALL VERTERATES)

The blood is contained within heart and vessles- not direct contact with any tissues of body (blood plasma apart of extracellular pool)

What connects veins and arteries/permeating tissues?

capillery beds

Confinements make.....possible.

pressue regulation, direction of flow, and high flow rates

Desrbie the heart

Muscular pump that creates pressue and direction flow in vasculature (in closed circulatroy systems)- blood travels in one direction

Creates directional flow in open circulatory systems

What maintaisn bulk flow of fluids? And during when?

The heart, in face of resustance of blood vessles (due to big vessels branching to smaller ones where increase of friciton and decrese in pressue)

What happens to blood pressure from heart to cappileries (closed system)?

Far from heart, BP drops

This is due to greaer total volume occupued (resistance)

What happens to blood velocity from heart to cappilereies (closed)?

Blood velocity descreases with distance to heart, this is due to smaller diameters of vessels osccupied (due to resistance).

What happens to blood pressure from capilleries to heart (closed)?

Blood pressure continues to drop

What happens to blood velocity from capilleries to heart (closed)?

Blood velocity increases due to increasing diamtere of vessels.

What are arteries (closed)?

AKA efferent vesselsCarry blood AWAY from the heart

Control blood distribution to body by resistance (diameter of vessel)

They are elastic/flexible

What are veins (closed)?

AKA afferent vesselsCarry fluid BACK TO HEART'

Store blood and are easily expanded

What are capillaries?

Allow exchange of substance between BLOOD and TISSUESThe morphology of wall allows diffusion (also due to LARGE SA)

What is blood (ECF) in vertebrates made of?

1. Plasma - water, ions, proteins, nutrients and gas

• The ions are Na+, K+, CL-, HCO3-, Ca++, and H+

• Proteins are globulins, albumin and firinogens

• Gasses are O2 and CO22.

2. Erythocytes - respiroty pigments like haemoglobin/haemocyanin- increase ability of fluid to carry CO2 and O23.

3. Leukocytes - white blood cells for immune system

4. Plateles- healing

What are things that can affect circulatory systems in vertebrates?

1. Whether or not gravty is a factor on blood flow

2. Where gas exchange happens

3. Thermoregulatroy mode (endo or ectothermy)

Describe the circulatory system for fish vertebrates (basal conditions)

1. two chambers- -Atrium: thin walled, receives O2 poor blood from body (systemic circulation)

• Ventricle: thick walled, muscular, send O2 poor blood through aorta to gills

2. Forms a single loops

3. Low pressure due to low gravity effect

Describe the vertebrates circulatroy system of tetrapods:

1. Have two seprate circuits -Low Pressure Pulmonary Circuit: Between heart and lungs -High Pressure System Circuit: Between heart and rest of body (high pressure because blood needs to travel far)

2. Each circuit has own atrum and increasing sepration of the ventricles into TWO chambers

3. Gravity is a factor

Vertevrate circulatroy system of ectohermic tetrapods:

Can bypass the pulmonary circuit while driving cutaneous respiration

Ectotherms can tolerate some deoxygenated blood mixed with oxygentated blood due to low metabolic rate and therefor have an incomplete seperation of ventricles

Descirbe the vertebrate circulatory system in mammals and birds:

Have complete seperation between ventricles.

Blood can only pass blood between pumonary and systemic (body) circuits at the heart

Endothermy requires efficient level of O2 delivery to tissues - due to high met rate

What the four reason gas exchange is nesessary?

1. Krebs Cycle and Oxidaditve phophorylation - consume O2 and produce CO2.

2. Photsynethesis - consume CO2 and produce O2.

3. pH regulation (CO2 reglation- formation of carbonic acid)

4. All plants and animals must breath *

How does ventilation help with gas exhange with enviornment?

Bulk flow betweeen the respitory medium (air/water) and the gas exhange surface (lungs ect)

Must move large ammounts of air over the membrane, and gas can enter/exit the extraceullular bulk flow fluid by DIFFUSION AKA oxygen into blood and CO2 out of blood

What are the levels that gas exchange takes place?

1. Between blood and air/water (at respiratory membrane)

2. Between blood and tissues

Both happens by diffusion

How is gas transport carried out?

By blood carrying gas through circulatory system

Describe partial pressue

Each gas that makes up the atmosphere contributes to the total atmospheric pressue.

The composition of atmosphere remains the same even if the pressure descrease with alutidue

Diffusion in gas exchanged in the body is based on..

partial pressure gradients

Describe partial pressue gradients in the body

Oxgyen and carbon dioxide partial pressures differ throughout the body, but the gradient is maintaind by the circulatory system

The CO2 produced in tissues has (high/low) partial pressue

High

The O2 produced in the tissues has (high/low) partial pressue

low

How does has exchange occur with the ECF?

There is a gas exchange surface where diffusion between air/water and the ECF can occur

The surface area of it is proporitonal to mass/metabolic rate (ie. if high metabolic rate, have a large gas exchange surface to ensure you get enoough o2)

What are the characteristics of a good gas exchange structure:

Reflects Fick's Law of Diffusion (greater SA, more diffusion)

Must have large surface area Be moist Be thin

How does gas exchange ocur with the ECF and tissues?

There is diffusion at capillereies, where a small diamter vessel is close to the walls

They increase the surface area and have thin wall (easier diffusion)

____ distance across membrane to ECF is nesseasry

SHORT (becasue difussion)

In mammals, the bulk flow of the ECF forms a...

unifrom pool

What is the gas partial pressure gradient maitained by?

movement of blood

mamilian (uniform pool) circulation has relativley poor...

gas exchange

What is the counter current exchange system in regards to gas exchange with the ECF?

Water and blood move in opposite direction to maintain constant partial pressure gradient along exchange surface

Highly effective gas exchange

Desrcribe the coutner current gas exhcange in birds (with regards to gas exhcnage with the ECF)

Air flows in one direction through rigid lungs (air sac system)

Two cycles of ventilation are nesessary - one breaths and one to clear the system

More effective gas echange system that uniform pool exchange

H+ is produced...

continuosuley in aerobic respiration (metabolic proccesses)

Why is acid base regulation important?

Proteins/enzymes only work at specific pH (and are required for biochemical processes)

Therfore, pH must be regulated

What does acid base regulation involve?

Production, retnetion, and removal of H+ through BICARBONATE BUFFERING MECHANISM