4th Bio Midterm

Lectures 30-35

what does osmotic concentration measure

• solution concentration per liter

• talking about solutes within water

who are the hyper and hypo relative to their environment

• osmoregulators

  • because they are different relative to their environment

osmoconformers

• have the same osmotic concentration as its environment

• isotonic relative to environment

• if you measured the solute in the organisms and outside it is the same

is isotonic passive or active

passive

osmoregulators

• control their osmotic concentration independently from the environment

• hyper/hypo relative to environment

• can modify or regulate their concentrations within their bodies

are osmoregulators changing actively or passively

• ACTIVELY

  • they are activity changing their osmotic concentration

  • you are actively pushing towards or against what is happening in the environment

if you say hyper or hypo what type of process is that

• an active process

hyper and hypo is RELATIVE to the environment and not is just a constant state

what is excretion

• process of moving nitrogenous waste

isotonic

• water concentration in organism and concentration of water in environment is equal

• water and salts are continuously diffusing

• seeing equilibrium but it ISNT static

what group of animals tend to be isotonic

• marine invertebrates

hypertonic

• concentration of water in organism is less than the concentration of water in the environment

• water moves IN, salts move OUT

hypotonic

• concentration of water in the organism is more than the concentration of water in the environment

what type hyper or hypo is in freshwater & describe what happens to maintain water balance

• hypertonic

  • organism is salty and water isnt

• gain water by osmosis and excrete large amounts of highly dilute (low concentration) urine to reduce excess water

• taking in water passively and ACTIVELY removing that water through excretion

• have too much water so are trying to regulate by actively moving water out when water is coming in passively

what type hyper or hypo in the ocean & describe how they adapt

• hypotonic

  • salty sea so organism has more water

• can get strongly dehydrated so drink a lot of seawater

• passively losing water and actively drinking water to regain it

• since the sea is salty, salt is constalty coming into the body and that makes you dehydrated

  • so you drink a lot

  • losing water gaining salt

what type hypo or hyper on land & describe what happens

• technically hypotonic

  • because there is less water on land so there is more inside of us

• see a constant loss of water on land from secretions, excretions, and evaporation

• we have strats to use on land to prevent water loss!

osmotic and tonic are the same

• ex. hypotonic and hypoosmotic = same thing

whatever is happening from high to low is passively but what they are doing to balance it is active

when is nitrogenous waste formed

• when we break down nucleic acids and proteins

• but these nitrogenous wastes are toxic so we need to excrete it

what animal do you have to be to make ammonia as a nitrogenous waste

• aquatic

  • but not all aquatic animals use it

ammonia

• toxic

• no internal water loss, must be diluted in water

• for aquatic animals

• release it into the environment

• takes little energy to make and there is no water loss involved

• good if you want to conserve water

urea

• low toxicity because has more bonds (but that means it takes a lot of energy to make =)

• leads to moderate water loss

• energetically costly

• mainly land animals

• diluted through water (we do this)

uric acid

• relatively non-toxic

  • so can store in your body

• doesn’t dissolve in water so it reduces water loss

  • when you remove it not losing water to do so

• LOTS of bonds so takes a lot of energy to make

• removed at the same time as elimination (peep and poop at the same time)

what type of animals make uric acid

• reptiles/birds, insects

what would make you produce more nitrogenous waste

• if you eat a lot of protein in your diet

• if you are an endotherm and need energy

what are the four basic steps of excretion

1. filtration

2. reabsorption

3. secretion

4. excretion

describe filtration

• create the filtrate made up of water and solutes that is collected from blood

• has good stuff and bad stuff

describe reabsorption

• reabsorb the things we want to keep using the filtrate we made

  • and put them back into the bloodstream

what do we always reabsorb

WATER

describe secretion

• some things that we want to remove aren’t passively moving into the filtrate

• so we ACTIVELY move in things we don’t want into the filtrate

describe excretion (the step not the whole process)

• let out what is left of the filtrate

  • in mammals that is urine

is secretion in excretion process passive or active

• active! because getting those things that aren’t moving passively into the filtrate

in mammals where does the steps of excretion happen

• in the nephron

describe the mammalian excretory system

• kidneys

• nephrons

where are the nephrons and what does this system do

• in the kidneys

  • and in the kidneys sits the excretory system

describe the nephron

• the long tube

  • has capillaries around it

what is the glomeulus

• a ball of capillaries surrounding the nephron

what is the bowman’s capsule

• it surrounds the glomerulus and sends the filtrate into the capillaries

what is the formation of filtrate facilitated by

• blood pressure

  • this forms the filtrate

• as blood pumps through the body there are pores through the capillariy and pushes the fluid into the bowman’s capsule

steps of mammalian nephron

1. bowman’s capsule

2. proximal tubule

3. loop of henle

4. distal tubule

5. collecting duct

where do you start when in the nephron

• bowman’s capsule

what is the function of the bowman’s capsule

• filtration is formed here

what is the function of the proximal tubule

• goes from bowman’s capsule

• reabsorption and secretion

• reabsorb water, salt, ions, nutrients

  • IMMEDIATELY

• secretion of toxins into filtrate

  • so actively moving toxins into the filtrate

reabsorption happens immediately

what is the function of the loop of henle

• reabsoption of water only

  • all about reabsorbing water

  • all about bringing water to put into bloodstream and back into body

• maintaining an osmotic gradient

  • so that water can always be moving passively

what is always moving passively in our kidneys

• water

  • so always needs to maintain a strong osmotic gradient so that water is always being put back into the body

what is the function of the distal tubule

• reabsorption

• rebalance

• some secretion as a double check

  • ions

what is the function of the collecting duct

• excretion

• final water reabsorption

• where we form the urea that then moves into the bladder

secretion happens in multiple locations but what types of things are being secreted into the proximal and the distal tubules

• proximal = TOXINS

• distal = ions

how do desert mammals do water conservation on land

• highly hypertonic urine

• many long nephrons maintain steep osmotic gradients

  • a long nephron because have more absorption of water because of high tonic urine

how do you concentrate your urine

• do more reabsorption

  • because you are actively reabsorbing things and making the filtrate more concentrated

the longer the nephron = the more time the time the filtrate spends = the steeper the osmotic gradient

freshwater mammals and conservation of water on land

• have more short nephron loops and lower urine concentration

• don’t have to worry about conserving water in their urine since live in water

the less you have to conserve water the better

because it is costly and takes energy

birds and conservation of water on land

• primarily produce uric acid

  • which is water efficient since don’t have to dissolve uric acid in water

benefit of producing uric acid instead of urea for birds

• they don’t have a bladder so they don’t have anywhere to store their uric acid

what do freshwater fish do to conserve water

• excrete large amounts of dilute urine

• conserve salts by reabsorping ions from filtrate

  • because they are losing salt to the environment

what do marine fish do to conserve water

• filtration rates low, little urine excreted

  • always losing water to environment so trying to keep as much as it can and excretes highly concentrated urine

• chloride cells in gills help maintain salt balance

  • have special cells to reduce the salt and maintain a salt balance

    • because they keep gaining it since in an ocean

best water conservation is seen where?

• dry places

  • because that is where water conservation is selected agains

• because trying to conserve their water

• retain more water

cellular respiration products and reactants

• requires oxygen and produces carbon dioxide

gas exchange

• uptake of oxygen from environment and the discharge of carbon dioxide to environment

what facilitates cellular respiration

• gas exchange

what type of respiratory surface do gases diffuse across

• moist respiratory surfaces

  • because have to dissolve into a liquid to amke it across that membrane

  • the respiratory surface is what is used for gas exchange

what are some general things that matter for gas exchange

• metabolic rate

• habitat

• animal size

• type of circulatory system (closed or open)

what is the best way to increase gas exchange effiency

• increase surface area

  • the area that they have to cross

marine invertebrates typically use…

• diffusion

  • through the skin

• because they are not metabolicly active and needs are low so get enough oxygen from diffusing

there is less oxygen in water than in air

diffusion isn’t enough when you have a closed circulatory system

when do we see selection for gills

• when we get more metabolicy active

what is the benefit of gills

• they give a larger surface area to increase efficiency

  • they are folded a lot

animals that use gills

fish, sharks, mollusks, crustaceans

what maximizes gas exchange in fish

• countercurrent flow

  • to make sure oxygen flows over their gills

increasing surface area can increase area for oxygen to get into the bloodstream and then there is an increased area for carbon dioxide to get out

insects are invertebrates

how do insects do gas exchange on land

• tracheae

• oxygen/carbon dioxide transfer completed by trachea

• hemolymph distributes nutrients, collects waste

what are tracheae

• air tubes that branch throughout body

• there are pores that connect the tracheae to the cells inside the body

  • and then go through these branches that are found close to every cell and delivers o2

what is separate in insects

• their circulatory system and oxygen deliver are separate

• in us we think of oxygen delivery as a circulatory system

insects acquire oxygen directly

what is the major thing we see with land gas exchange when we shift to vertebrates

• lungs

first group to have lungs

• ray finnned fish

almost all tetrapods have lungs (except lungless salamanders)

not all tetrapods have a fully developed ribcage

gets ribs when we get a spinal cord

tetrapods

• amphibians, mammals, reptiles/birds

amniotes are the first gropu with a really developed ribcage

what do lungless salamanders use to breathe

• cutaneous

what is the primary/sole gas exchange organ for tetrapods

• lungs

the complexity in reptiles and mammals increases surface area

what increases our surface area in gas exhange in mammals

• the alveoli

alveoli increase surface area so have more contact with the capillaries with the diffusion surface and move oxygen into the body

purpose of breathing

• to increase the rate that gas exchange happens

  • to maintain high o2 and low co2 at the respiratory surface

• maintaining concentration gradient

describe breathing in amphibians

• don’t have a well developed rib cage

  • can’t move around their rib in breathing

• lower lung surface area than amniotes

  • don’t have as much gas exchange in their lungs since they do pulmocutaneous

• use positive pressure breathing

• exhale = just open mouth

describe positive pressure breathing

• facilitates gas exchange

• lowers floor of throat during inspiration and then force air from the oral cavity into their lungs by contracting their throat muscles

  • pull air in and then push it

• kinda like swallowing air

what type of process (passive or active) is positive pressure breathing

• ACTIVE

  • because pulling air in and pushing it out

positive pressure breathing requires…

• force

describe breathing in birds

• they have to be highly efficient

• they have air sacs that act as bellows to keep air flowing

  • they force area around the body

• 2 cycles of inhalation/exhalation for air to complete circuit

• unidirectional air flow

what is a bellow

• in a bird

• lilke an accordian and use this structure to push air around their body

describe the 2 cycles of inhalation/exhalation in birds

• they breathe air first into posterior air sac (inhalation), then lungs (exhalation), then from there to anterior air sac (inhalation), and then from the anterior air sacs and out the mouth (exhalation)

why do birds have 2 cycles of inhalation/exhalation

• to allow for unidrectional airflow

what is unidirectional air flow in birds

• fresh air and oxygen-reduce air don’t mix

  • breathe out air (co2 rich) and breathe in air (oxygen rich) don’t mix

• so don’t dilute oxygen in the system (efficency!)

• oxygen and carbon dioxide don’t interact