Introduction to Animal Physiology Chapter 20

Just like in plants

Let’s take each of these one at a time.

What type of tissue is composed of cells embedded in a matrix What type of tissue is composed of cells embedded in a matrix? a) nervous b) epithelial c) muscle d) connective e) None of the above are correct.

Which of the following is a main benefit of multicellularity? a) Each cell can perform all of the necessary physiological processes needed by the body. b) Each cell can dump its waste directly into the environment. c) Only some body cells need to make ATP.  d) Cells can divide up the labor of performing essential physiological processes. e) Each cell has direct access to nutrients in the environment.

Body Organization Different types of tissues working together for a common function = organ Different organs working together for a common function = organ system

Organ Systems Overview

Which organ system(s) control or regulate body activities? a) nervous system b) endocrine system c) circulatory system d) immune system e) Both a) and b) control or regulate body activity.

What is the function of the respiratory system? a) exchange gases between the internal and external environment b) recycling fluids that leak from the circulatory system c) transport gases to and from tissues in the body d) make ATP from glucose and other energy-rich molecules e) purify the blood by filtering out wastes

Homeostasis – Maintaining a stable internal environment

Homeostasis varies

What are advantages of each?

Various methods for maintaining body temperature: physical such as fat insulation, behavior such as body position or nest orientation to max absorbing radiation from sun, physiological such as panting or sweating to gain evaporative cooling, Cellular such as metabolic processes that generate heat and warm body.

Excretory System 2 main functions: Maintains the proper water balance for body Cleans blood of waste bi-products

What is osmosis? The diffusion of water across a semi-permeable membrane Why should we care? Our cells are sacs with semi-permeable membranes Without the proper balance of water in cells, life systems shut down

Osmosis con’t Water will move from a dilute solution to a concentrated solution Salt concentration - # water molecules/# salt ions

Relative Osmotic Pressure Demonstrated in the last slide Concentration of solutions relative to adjoining solutions (one cell to the next cell or body relative to surroundings, etc.) Ex. Red Blood Cell in different solutions Which one is in a saltwater solution (hypertonic), saline (isotonic), freshwater (hypotonic) Cell membrane will allow water to cross membrane freely but not other ions or molecules. A B C

Real world problems relative to this issue: Different environments present different problems Marine – tendency to gain salt + lose water Freshwater – opposite – gain water, lose salt Terrestrial – dry – very hypertonic Humans drink 2300 ml/day get 200 from metabolism gain 2500 Urinate 1500 ml/day Lost due to evaporation: 1000 ml/day

Solutions to water balance problems: Physical barriers to water movement Scales on fish, cuticle, hair, feathers Pump water or salt from body Urinate, flame cells of Planaria Salt glands of marine birds and reptiles Pump water or salt into body Drink Freshwater fish have gill pumps that take in salt and concentrates it in the blood

2nd Function: Waste Removal Waste – what is it? Ammonia (NH3) is the most toxic Biproduct of protein breakdown If eliminated in its pure form – needs to be with lots of water – ex. Freshwater animals If terrestrial and need to conserve water – Ammonia is changed to a less toxic form Chemical change requires energy Urea – 2 ammonia + CO2 (fish, amphibians, mammals, some invertebrates) Uric Acid – ring structure = powdery product (terrestrial organisms in dry locations)

Other Wastes: Excess Ions Toxins Excess vitamins Other unneeded breakdown products Ions = Na, H, K, Cl, Mg, Ca

Systems vary among animals Single celled animals – contractile vacuoles Earthworms – tube with cilia filters coelomic fluid and blood vessels associated with tube give off waste from blood

Mammals – ex. Human Body has different fluid compartments: Blood - 5% body wt Interstitial -15% body wt (lymph collects and returns to blood) Intracellular (inside cells of body) – 50% body wt All accumulates waste and needs to be filtered and cleaned. Cell waste dumped into interstitial, lymph puts that into blood. Blood is filtered and cleaned.

Parts of Excretory System Urethra has a sphincter that allows voluntary control up to a point. Kidney = mj osmoregulatory + excretory organ in mammals.

Nephron 1 million/kidney

Secrete molecules/ions into nephron Filter blood Secrete molecules/ions into nephron Reabsorb some ions/molecules Regulate amount of water lost Eliminate urine 1. Blood pressure high in glomerulus due to control of muscle control of walls of afferent and efferent blood vessels 1/5 of blood plasma is forced into Bowman’s capsule from glomerulus capillaries. All but larges molecules.

Secretion (2) Reabsorption (3) Selective (requires energy) transport of additional molecules in blood into proximal tubule Reabsorption (3) Selective (requires energy) transport of needed substances back into blood Most of water, solutes such as sodium, amino acids and glucose Proximal tubule

Osmoregulation (4) Loop of Henle Salt gradient in cortex and medulla of kidney Medulla high conc Water removed from tubes Bottom of loop – inside tube = hypertonic Upward arm of Loop – membrane not permeable to water Salts pulled out More water pulled out through wall of collecting duct Proximal tubule – isotonic; Loop moves down into medulla

Distal Tubule (2 +3) Collecting Duct Drugs and toxins removed from blood Again much by active transport (requires energy) Collecting Duct Eliminates urine (5) Proximal tubule – isotonic; Loop moves down into medulla

What is the correct order of flow through the parts of a nephron? Bowman’s capsule, proximal tubule, loop of Henle, distal tubule, collecting duct Loop of Henle, Bowman’s capsule, proximal and distal tubules, collecting duct Proximal tubule, loop on Henle, distal tubule, collecting duct, Bowman’s capsule

High blood pressure needed for whole system to work High blood pressure needed for whole system to work. If lose blood pressure for any reason, kidneys can fail, body rapidly becomes poisoned by accumulating waste. Also high energy requirements for proper function.HCO3 = bicarbonate.

High blood pressure medication can be simply a diuretic High blood pressure medication can be simply a diuretic. How would this work to lower blood pressure? Diuretic = makes collecting ducts less permeable to water, so more is lost in urine. What could be the body’s response to a drop in blood pressure? – Vein walls contract – correct volume in heart and arteries.

Antidiuretic Hormone (ADH) Drop in blood pressure detected by heart sensors Sensor information stimulates hypothalamus to secrete ADH ADH makes collecting ducts more permeable to water More water reabsorbed and retained by body, blood volume increases, blood pressure increases Feedback loop – increased in blood pressure turns off hypothalamus secretion. ETOH inhibits ADH release. Caffine dialates blood vessels, lowers blood pressure, causing ADH secretion and water retention.

Animation for Ch 20 7.5 min

________________ gain most of their heat from their environment, while _________________ can use metabolic heat to regulate their body temperature. a) Endotherms; ectotherms b) Plants; animals c) Fungi; animals d) Birds, lizards e) Ectotherms; endotherms

Which is the correct order of the processes used by the kidney in forming urine? a) reabsorption > filtration > excretion b) filtration > reabsorption > excretion c) excretion > filtration > reabsorption d) filtration > excretion > reabsorption e) excretion > reabsorption > filtration What are the parts of the nephron involved with each process?

Read Chapter 21 Circulation & Respiration