U NIT 16 (C H. 22) G AS E XCHANGE & E XCRETION How do organisms: Obtain oxygen and eliminate carbon dioxide? (or vice versa…in plants?) Maintain osmotic balance? Excrete nitrogenous waste products? 300

G AS E XCHANGE ( CH 22.1) ♦ What gases are exchanged ? ♦O2♦O2 ♦ CO 2 ♦ By which process are gases exchanged? ♦ diffusion

G AS E XCHANGE ♦ What conditions are required for gas exchanged? ♦ gas must be dissolved in a liquid ♦ large surface area ♦ Why? ♦ to maximize exchange ♦ protection of structures ♦ Which system does the respiratory system often work with in animals? ♦ circulatory (transport) system

G AS E XCHANGE IN U NICELLULAR & S IMPLE M ULTICELLULAR O RGANISMS ♦ How is gas exchange carried out in simple organisms? ♦ diffusion directly with moist environment

G AS E XCHANGE IN P LANTS ♦ Where does gas exchange occur in plants? ♦ no specialized gas transport system b/c different locations ♦ roots ♦ root hairs ♦ stems ♦ lenticels ♦ leaves ♦ gases enter/exit through stomata and move into air spaces of spongy layer ♦ exchange occurs at moist surface of cells surrounding air spaces

G AS E XCHANGE IN M ORE C OMPLEX A NIMALS ♦ Usually carried out by respiratory system. ♦ acquire O 2 from environment, distribute it through body, & discharge CO 2 ♦ “respiration”

G AS E XCHANGE IN A NIMALS ♦3♦3 “types” of respiration: ♦e♦external respiration: ♦b♦breathing ♦i♦internal respiration: ♦e♦exchange of O 2 & CO 2 between air sacs & capillaries (or cells) ♦c♦cellular respiration: ♦C♦C 6 H 12 O 6 + 6O 2 → 6H 2 O + 6CO 2 + energy (ATP)

E ARTHWORM ♦ gases diffuse through moist skin

G RASSHOPPER ♦ air enters spiracle s (openings) ♦ lead to tracheae (tubes) ♦ tracheae branch repeatedly ♦ ending in moist tracheoles (air sacs) ♦ gas exchange (diffusion) – aided by muscle mvmt

F ISH ♦ operculum or gill cover ♦ protection ♦ H 2 O enters mouth & flows over gills ♦ CO 2 diffuses blood  H 2 O ♦ O 2 diffuses H 2 O  blood

♦ How does the amount of O 2 dissolved in water change in relation to water temp.? F ISH ♦ Which of these descriptions best explains the decrease in the breathing rate of the goldfish? a) The demand for O 2 increased. b) The rate of metabolic activity decreased. c) The demand for CO 2 decreased. d) The fish's activity levels increased. Virtual Fish Respiration Lab

R ESPIRATION IN H UMANS ♦ What path does air follow when inhaling? ♦ nose → pharynx → larynx → trachea → bronchi → bronchioles → alveoli ♦ gas exchange: alveoli ↔ capillaries capillaries How are alveoli an adaptation? Gas Exchange Animation 1 Respiration Animation Epiglottis prevents food from entering trachea. What is the function of the cartilaginous rings around the trachea?

H UMAN R ESPIRATORY S YSTEM capillaries

♦ What happens in the lungs during gas exchange? ♦ alveoli have high level of O 2 & low level CO 2 ♦ O 2 diffuses from alveoli  blood in capillaries (combines w/ hemoglobin in red blood cells) ♦ blood in capillaries has high level of CO 2 & low level of O 2 ♦ CO 2 diffuses from blood  alveoli ♦ & is exhaled RESPIRATION IN HUMANS

♦ What happens in the cells/ tissues during gas exchange? ♦ cells/tissues have high level of CO 2 & low level of O 2 ♦ CO 2 diffuses from cells/tissues  blood in capillaries ♦ blood in capillaries has high level of O 2 & low level of CO 2 ♦ O 2 diffuses from blood in capillaries  cells/tissues RESPIRATION IN HUMANS

Gas Exchange Animation 3 Gas Exchange Animation 2 Gas Exchange Animation 1

♦ Do you have to remember to breathe? ♦ No, medulla (brain stem) controls breathing. ♦ responds to blood’s CO 2 levels ♦ CO 2 too high  breathe faster R ESPIRATION IN H UMANS

♦ What happens to your breathing rate when you exercise? Why? ♦ increases to adjust rate of gas exchange to needs of cells ♦ b/c CO 2 levels increase & O 2 decrease R ESPIRATION IN H UMANS

♦ What happens to the diaphragm and ribs during inhalation? ♦ diaphragm contracts (pulls down/flattens) ♦ ribs raised (move up/out) ♦ Does the chest cavity gets bigger or smaller? ♦ bigger (expands) ♦ What happens to air pressure in the lungs? ♦ becomes lower inside than outside ♦ Which way does air move? ♦ air rushes in R ESPIRATION IN H UMANS

♦ What happens to the diaphragm and ribs during exhalation? ♦ diaphragm is relaxed ( pushes up/arches) ♦ ribs lowered (move down/in) ♦ Does the chest cavity gets bigger or smaller? ♦ smaller (compresses) ♦ What happens to air pressure in the lungs? ♦ becomes higher inside than outside ♦ Which way does air move? ♦ air rushes out R ESPIRATION IN H UMANS

RESPIRATION IN HUMANS: CONTROL OF BREATHING Pressure higher inside, lower outside Pressure higher outside, lower inside Remember… “High, low…”

RESPIRATION IN HUMANS: CONTROL OF BREATHING Kid's Health Respiratory System & Breathing

E XCRETION OF METABOLIC WASTE & M AINTENANCE OF O SMOTIC B ALANCE CH. 22.2

E XCRETION OF METABOLIC WASTE … IS DIFFERENT FROM THE ELIMINATION OF DIGESTIVE WASTES !

E XCRETION ♦ What is excretion? ♦ removal of wastes produced from metabolism of nutrients (& other non-useful materials) ♦ CO 2 ♦ excess water ♦ nitrogenous waste ♦ All metabolic wastes removed through excretory organs (nephridia, Malpighian tubules, kidneys) ♦ exception = CO 2, excreted with water vapor through lungs

E XCRETION ♦W♦Why must cellular wastes be removed? ♦c♦can be toxic ♦W♦Which life characteristic does excretion relate to? ♦h♦homeostasis

♦m♦mostly from protein metabolism ♦&♦& some from nucleic acids ♦a♦amino groups quickly pick up H ♦t♦to become a mmonia ♦h♦highly toxic ♦m♦may be excreted directly or converted to less toxic forms ♦u♦urea ♦u♦uric acid N ITROGENOUS W ASTE

♦a♦ammonia ♦e♦excreted by aquatic organisms ♦u♦urea ♦e♦excreted in small amount of water ♦♦ urine ♦u♦uric acid ♦i♦insoluble ♦e♦excreted as crystals ♦i♦in arid environments N ITROGENOUS W ASTES How is the production of urea/uric acid an adaptation to life on land/dry environments? H 2 O conservation

O SMOTIC B ALANCE ♦ concentration of dissolved particles in liquid inside & outside cell is the same (isotonic) ♦ What if the concentrations are different? ♦ hypotonic ♦ cytolysis ♦ hypertonic ♦ plasmolysis ♦ Adaptations for waste removal may also be responsible for maintaining osmotic balance Importance of H 2 O: reactions, part of blood, disperse heat

SALT WATER ORGANISMS ♦ excretion ♦ ammonia is soluble ♦ diffuses from (cells) into water ♦ osmotic balance ♦ naturally in balance ♦ no special adaptations needed

F RESH W ATER O RGANISMS ♦ excretion ♦ waste diffuses from (cells) into water ♦ osmotic balance ♦ not naturally in balance (hypotonic environment) ♦ Adaptations to help maintain? ♦ contractile vacuole ♦ ex. Paramecium Video of Paramecium--Contractile Vacuole

♦ Planaria ♦ excretion of wastes & osmotic balance ♦ system of excretory canals & flame cells ♦ canals branch into excretory ducts ♦ open as pores on the surface F RESH W ATER O RGANISMS

L AND A NIMALS ♦ cannot diffuse ammonia ♦ must convert to urea or uric acid ♦ can safely build up in body fluids until excreted ♦ wastes transported by blood or tissue fluid ♦ system excretes N-wastes & is a factor in osmotic balance ♦ H 2 O conservation emphasized Uric acid

♦ ammonia ♦ diffuses through skin ♦ into soil moisture ♦ urea ♦ eliminated through nephridia ♦ filtering organs LAND ANIMALS: EARTHWORM

♦ Malpighian tubules ♦ filter blood ♦ reabsorb water ♦ uric acid enters intestine ♦ excreted thru anus ♦ Why is ammonia converted uric acid (crystals)? ♦ H 2 O conservation LAND ANIMALS: GRASSHOPPER

♦ Habitat? ♦ desert ♦ Can survive without drinking H 2 O. ♦ How is this possible? ♦ gets water from food ♦ extremely efficient kidneys ♦ reabsorbs almost all water that passes through them ♦ excretes very concentrated urine L AND A NIMALS : Kangaroo RatKangaroo Rat

H UMAN E XCRETION ♦ Which parts of the human body carryout excretion? ♦ lungs ♦ CO 2 & H 2 O (vapor) ♦ skin ♦ H 2 O & salts ♦ = sweat ♦ urinary system ♦ urea, H 2 O, salts ♦ = urine

HUMAN EXCRETION ♦ What are the parts of the urinary system? ♦ kidneys (& associated blood vessels) ♦ main excretory organ ♦ ureters ♦ (urinary) bladder ♦ urethra

HUMAN EXCRETIONHUMAN EXCRETION: THE KIDNEY ♦m♦main excretory organ ♦3♦3 parts ♦o♦outer part ♦c♦cortex ♦i♦inner layer ♦m♦medulla ♦i♦inner collecting area ♦p♦pelvis

5 STEPS TO HOW KIDNEYS WORK 1. blood w/ waste brought to kidneys from renal artery 2. blood is f iltered by nephrons (by diffusion) 3. wastes pass thru ureters to bladder as urine 4. clean blood sent back to body thru renal vein 5. bladder stores urine (until passes out of body thru urethra) 1 million nephrons per kidney!!! How Kidneys Work Video

♦ What is a nephron? ♦ functional unit of the kidney ♦ responsible for filtration of waste from blood ♦ ~1 million nephrons per kidney!!! NEPHRON

NEPHRON: STRUCTURE ♦ nephron consists of: ♦ Bowman’s capsule ♦ cup-shaped ♦ surrounds glomerulus ♦ narrows into coiled tubule

NEPHRON: STRUCTURE ♦g♦glomerulus ♦m♦mass of capillaries in center of Bowman’s capsule that forms f rom branch of renal artery ♦c♦carries unfiltered “waste-filled” blood to nephron ♦a♦another arteriole loops away from glomerulus & divides into capillaries that surround t ubule

♦ capillaries surround tubule ♦ merge to form venules & veins ♦ which merge to form renal vein which returns filtered blood back to body

PROCESSES IN THE NEPHRON ♦ filtration of blood/ urine production ♦ requires three distinct processes: 1. glomerular filtration 2. tubular reabsorption 3. tubular secretion ♦ excretion of urine

♦ 1. filtration ♦ “waste-filled” blood brought to kidney by renal artery ♦ blood pressure forces plasma from blood in glomerulus into Bowman’s capsule of nephron ♦ this liquid = filtrate (water, urea, salts, glucose, amino acids & other dissolved materials) ♦ large proteins & blood cells do not enter PROCESSES IN THE NEPHRON

♦2♦2. tubular reabsorption ♦f♦filtrate travels through nephron in tubule ♦n♦needed materials are reabsorbed into surrounding capillaries ♦e♦ex. most of water, salts, glucose, vitamins, etc. ♦b♦by active or passive transport ♦e♦excess materials remain in the collecting duct ♦w♦water, urea, salts ♦c♦concentrated fluid = urine tubule. PROCESSES IN THE NEPHRON

♦ 3. tubular secretion ♦ molecules present in blood in great excess (or natural poisons) may be removed from capillaries & transferred to tubules for excretion ♦ often by active transport ♦ ex. drugs such as antibiotics ♦ “clean” blood sent back to body through renal vein PROCESSES IN THE NEPHRON

♦ excretion ♦ urine (urea, excess salt, small amount of water) leaves nephron & passes from collecting duct to renal pelvis ♦ leaves kidney via ureters ♦ to bladder where stored until once filled & urine is excreted through urethra (urination) How Kidneys Work Video PROCESSES IN THE NEPHRON

PROCESSES IN THE NEPHRON

PROCESSES IN THE NEPHRON

PROCESSES IN THE NEPHRON