Introduction to Animal Physiology

Chapter 20

What type of tissue is composed of cells embedded in a matrix?

a) nervousb) epithelialc) muscled) connectivee) 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 systemb) endocrine systemc) circulatory systemd) immune systeme) 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

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

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 solutionsA 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 2500Urinate 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

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

Parts of Excretory System

Nephron1

million/kidney

1. Filter blood

2. Secrete molecules/ions into nephron

3. Reabsorb some ions/molecules

4. Regulate amount of water lost

5. Eliminate urine

Secretion (2)› 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

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

Distal Tubule (2 +3)› Drugs and toxins

removed from blood› Again much by

active transport (requires energy)

Collecting Duct› Eliminates urine (5)

What is the correct order of flow through the parts of a nephron?

a) Bowman’s capsule, proximal tubule, loop of Henle, distal tubule, collecting duct

b) Loop of Henle, Bowman’s capsule, proximal and distal tubules, collecting duct

c) Proximal tubule, loop on Henle, distal tubule, collecting duct, Bowman’s capsule

High blood pressure medication can be simply a diuretic. How would this work to lower blood pressure?

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

Animation for Ch 20

________________ gain most of their heat from their environment, while _________________ can use metabolic heat to regulate their body temperature.

a) Endotherms; ectothermsb) Plants; animalsc) Fungi; animalsd) Birds, lizardse) Ectotherms; endotherms

Which is the correct order of the processes used by the kidney in forming urine?

a) reabsorption > filtration > excretionb) filtration > reabsorption > excretionc) excretion > filtration > reabsorptiond) filtration > excretion > reabsorptione) excretion > reabsorption > filtration

Read Chapter 21Circulation & Respiration