Exam 3 study guide

These are the topics to study for the exam

Lecture 1 Animal Structure and Function

Keywords: metabolic rate, collagen, ascorbate, hydroxyproline, bioenergetics, scaling

Objectives of the second half of the course

Learn how animals, plants, and bacteria work.

Understanding of relationship between organism function and physical principles

Linkages between biochemistry/cell biology and whole organism function/ecology

This section introduces overall themes we will come back to:

1) Organisms have similar functional needs

2) Organisms must obey physical laws

3) Understanding how an organism works involves consideration of biochemistry, cell biology, physiology, ecology and evolution

1. Organisms have similar functional needs

bacterium vs. sea anemone vs. shark (not much detail on this)

2. Organisms must obey physical laws

physical principles are evident from structure and function at organismal, cellular, and biochemical levels

Example: Size Does Matter (scaling effects)

What is it like for a mayfly to hatch out of a stream?

E. coli swimming in water -- is like a human swimming in hot asphalt

How do insects cling to vertical surfaces?

Example: scaling of skeletons

Is it possible to have 12 foot tall humans?

Have to consider scaling effects

What happens if you double the

linear dimension of an animal?

To avoid weaker skeletons on large animals, the skeleton size increases disproportionately

The relationship between skeleton size and body mass for a variety of mammals

A mouse-sized elephant would have a skeleton around 5 times heavier than a mouse

3) To understand how the functional needs of organisms are met, we need to integrate information about:

Biochemistry

Cell biology

Physiology

Evolution and Ecology

Collagen

most abundant protein of mammals

skin, bone, tendon, cartilage, and teeth

Great tensile strength

3 helical polypeptides nearly 1000 residues long

repeated (...glycine-x-x-glycine-x-x…) amino acid sequence

Often Glycine-proline-hydroxyproline

Primates and guinea pigs cannot synthesize ascorbate (Vitamin C)

Ascorbate is vital for the enzymatic conversion of proline (pro) to hydroxyproline (hyp)

In scurvy patients, collagen has an amino acid sequence of gly-X-pro rather than gly-X-hyp

Why does the improper amino acid sequence have deleterious effects?

Collagen of scurvy patients has a low melting temperature

Melting temp = 24° C for gly-X-pro in scurvy patients compared with 58° C for gly-X-hyp in normal people

Animal Diversity

Figure 32.4 A traditional view of animal diversity based on body-plan grades

Figure 32.5 Body symmetry

Figure 32.13x Burgess Shale fossils

Figure 33.1 Review of animal phylogeny

Phylum Porifera

Sponges
"colony" of flagellated cells
individual cells can potentially regenerate into a new individual

symmetry?

Phylum Cnidaria

Hydras, jellyfish, sea anemones, corals
gastrovascular cavity
stinging cells
Radial symmetry

Phylum Ctenophora

Comb jellies
comblike ciliary plates
gastrovascular cavity
Radiata (radial symmetry)

Bilateral symmetry

Figure 32.6 Body plans of the bilateria

Phylum Platyhelminthes

Flatworms
dorsoventrally flattened
no segmentation
gastrovascular cavity
bilateral, no coelom, protostome

Phylum Rotifera

Ciliated crown
no digestive system
bilateral, pseudocoelomates, protostome

Phylum Nematoda

Roundworms
unsegmented
no circulatory system
bilateral, pseudocoelomate, protostome

Lophophorates - several phyla

Bryozoans, lampshells (brachiopods)
bilateral, coelomate, protostome

Phylum Mollusca

Clams, snails, squids
foot, visceral mass, mantle
bilateral, coelomate, protostome

Figure 33.16 Basic body plan of mollusks

Table 33.3 Major Classes of Phylum Mollusca

Figure 33.21 Anatomy of a clam

Phylum Annelida

Segmented worms
bilateral, coelomate, protostome

Figure 33.23 Anatomy of an earthworm

Phylum Arthropoda

Crustaceans, insects, spiders
segmented body, jointed appendages, exoskeleton
bilateral, coelomate, protostome

Deuterostomes

Figure 32.7 A comparison of early development in protostomes and deuterostomes

Phylum Echinodermata

Starfish, sea urchins
bilateral, coelomate, deuterostome

Phylum Chordata

Lancelets, tunicates, vertebrates
notochord, nerve cord
bilateral, coelomate, deuterostome

Circulation and Gas Exchange I (Chapter 42)

Keywords

cellular respiration

Diffusion of gases

Speed of diffusion

Effect of size on oxygen supply

Gas exchange structures

Gills, lungs

Gastrovascular cavity

Surface area

Cellular respiration

A type of controlled combustion:

Reduced carbon (e.g., glucose) + O2

-------> CO2 + H2O

Organismal respiration -- a simple view (understand the cartoon picture in lecture notes)

Differences are observed in types of respiratory surfaces This will be the focus of today’s lecture

One major causes for these differences: Being big vs. small

Rate of diffusion of gases (e.g., oxygen)

How fast is diffusion of oxygen?

1 micron (µm) in 10-4 seconds

One millionth of a meter in one tenth of a millisecond

How does diffusion work?

Consider a point source of a diffusing substance

Each molecule will travel randomly (brownian motion)

Over time particles will become separated

But particles don’t just move away from the original point source

They are travelling randomly

Thus it takes a long time for molecules to diffuse over long distances

"Speed" of oxygen diffusion in liquid

1 µm in 10-4 seconds

1000 µm (1 mm) in 100 seconds

Thus diffusion can supply oxygen only over very short distances

Examples where oxygen diffuses only short distances

Vertebrate lung

Very small organisms

How small does an organism have to be to rely on diffusion alone?

Consider a spherical sea creature 1 mm wide

oxygen concentration in normal seawater is sufficient to support low rates of respiration

Predicted that oxygen concentration only needs to be 71% of normal levels

How about a spherical sea creature 1 cm wide?

The oxygen concentration in the water would need to be 71 times normal levels to support a low metabolic rate

Relationship between surface area and volume changes as a function of size

Another example of scaling

Example of organism relying solely on surface: the Protist Paramecium

Paramecium is a freshwater ciliate

Other small organisms that use their surfaces only include: bacteria, microalgae, yeasts

What do you do if you want to be bigger than 1 mm?

Adaptations to enhance gas exchange:

Circulatory systems and/or increased surface area

Example of increased surface area: Green Hydra (several mm long)

The jelly fish Aurelia

Complex gastrovascular cavity that circulates fluid

What are all the possible gas exchange structures?

Surface only (very small organisms 2 1 mm)

Gastrovascular cavity (hydra, jellyfish, also flatworms)

Gills, tracheal systems, lungs

Mixture of the above

Gills (definition)

Appendages around which the medium (usually water) passes.

often richly supplied with blood vessels

Found in many types of invertebrates and vertebrates

Circulation and gas exchange II (Chapter 42)

Keywords

Fish gill

Filaments

Lamellae

Tracheal system

Tracheoles

Gastrovascular cavity

Lung

Tidal ventilation

Ventilation in birds

Fish Gill

Rather than being a solid structure, the fish gill is finely subdivided to enhance gas exchange area

Definitely know these structures and terms: filaments, Lamellae,Countercurrent flow

**How does countercurrent flow enable more complete removal of oxygen from the water**

Are gills effective in increasing surface area?

In mackerel 20 fold increase due to gills

How do gill surface areas compare among different fishes?

Tracheal systems in insects, what are the parts? Can you identify them in the diagram. What is the tracheal system full of air? Liquid?

Know how Tracheoles supply tissues- how close is tracheole to individual mitochondria in cells

Lungs

Internal sacs

Unlike insect tracheal system lungs do not contact entire body

Circulatory system draws oxygen from lungs to tissues

Found in snails, a few fishes, spiders, vertebrates

Structure of the mammalian lung - main structure need to know is alveoli and that alveoli are surrounded by capillaries

Tidal ventilation of mammalian lung

Negative pressure breathing

Tidal volume - volume inhaled and exhaled (around 500 ml in humans)

Tidal volume is much less than total volume of lungs (several liters in humans)

Thus residual volume remains after exhaling

Why is tidal ventilation inefficient?

Birds have a more "sophisticated" type of lung ventilation

Birds have high metabolic rates

Can be exposed to lower oxygen concentrations in high altitude flight

Ventilation is not tidal

Air flows through the lungs

The avian respiratory system - know the structure and the direction of airflow. Know positions of mouth, anterior and posterior airsacs, lung.

The control of breathing- is it regulated by oxygen or carbon dioxide

Human brain monitors carbon dioxide level (detected as a drop in blood pH)

Hyperventilation in divers

Diving mammals can tolerate high blood carbon dioxide

Decreased oxygen corresponds to increased carbon dioxide

Increased carbon dioxide results in acidification which can readily be detected

Lecture 4: Circulation and Gas Exchange III

Circulatory System

keywords

Open vs. closed circulatory systems

Hemolymph vs. blood

Artery, capillary, vein

2-, 3-, 4- chambered heart

Pathway of circulation

Atrium

ventricle

Circulatory Systems

Two types: open and closed

Used to transport oxygen to cells and waste carbon dioxide away.

Also transport of other substances such as hormones, glucose, nitrogenous wastes

Open circulatory system

Found in invertebrates such as clams and insects

Heart pumps fluid to through vessels out to body into spaces called sinuses.

Fluid in sinuses bathes cells and organs

This fluid is called hemolymph not blood

Hemolymph collecting in sinuses can be drawn back into the heart.

Body movements can aid circulation by squeezing sinuses and pushing blood back into the heart.

Example of open circulation

Closed circulatory system

Found in earthworms (annelids), squids&octopus (cephalopods), vertebrates

Fluid (called blood) stays in the vessels

Smaller branching vessels supply tissues

Example of closed circulatory system: Earthworm

Compare and contrast open vs. closed

Open less effective at circulating all the fluid

Doesn’t matter if metabolism is slow, e.g., clams

Insects use trachael system to supply oxygen and get rid of carbon dioxide

Closer look at closed circulatory system

Also called cardiovascular system: heart, blood vessels, blood

Three main types of blood vessels

Arteries, capillaries, veins

Arteries are thicker walled, veins have valves

Arteries transport blood AWAY from heart, veins TOWARDS heart

Doesn’t necessarily correlate with oxygenated vs. deoxygenated blood

The vertebrate circulatory system- types of hearts

Two chamber - fish

Three chamber - amphibians

Four chamber - mammals, crocodiles

2-chamber - know the pathway of blood

3-chamber- know the pathway of blood

4 chamber- know the pathway of blood

What are the advantages of 3 chamber over 2 chamber? 4 chamber over 3 chamber?

Chemical signals in animals

Keywords

Endocrine system
Hormone
Neurosecretory cell
Steroid
Action of steroids
Glucose homeostasis
Insulin
Glucagon
Epinephrine
Norepinephrine
ACTH

Endocrine system definition

The internal chemical communication system involving hormones

The endocrine and nervous systems often function inseparably

We’ll look at specific examples that illustrate this.

Hormone

Chemical signal secreted into body fluids (usually blood)
Effective in minute amounts

Types of hormones

Steroid
Amino acid derived

Steroid hormones

Made from cholesterol
Include sex hormones

Amino acid derived

Single amino acids
Peptides
Proteins
glycoproteins

Hormones act on specific target cells in two ways

Surface receptors
Within target cells (internal receptor)

Surface receptor

Internal receptor

Action of steroids

Two examples of hormone action

Glucose homeostasis
Stress and the adrenal gland

Glucose homeostasis

Homeostasis = The steady-state physiological condition of the body
Glucose = major fuel of cellular respiration
Normal blood glucose level = 900 mg/L
How is this regulated?
First look at when glucose levels are too high

High blood glucose causes beta cells to release insulin

What happens if you need to increase blood glucose?

Low blood glucose causes alpha cells to release the hormone glucagon

Glucogon stimulates the liver to break down glycogen releasing glucose

Diabetes mellitus

Greek = copious urine, honey
Type I - autoimmune disorder - cells of pancreas are targeted - no ability to produce insulin - usually occurs during childhood
Type II (90%) - reduced responsiveness of target cells or insulin deficiency-usually occurs after age 40

Stress and the adrenal gland

Short-term response - Epinephrine (adrenaline) and norepinephrine
Long-term response - ACTH and corticosteroids

Short-term stress: medulla of the adrenal gland

Some effects of epinephrine and norepinephrine

Glycogen broken down to glucose
Increased blood pressure, breathing, metabolic rate

Long-term stress: cortex of the adrenal gland

Corticosteroids (mineral- and gluco- corticoids) released by adrenal cortex

Some effects: increased blood volume and blood pressure, breakdown of protein and fats

Animal Nutrition I

Keywords

Heterotroph

Autotroph

Herbivore

Carnivore

Omnivore

Intracellular digestion

Food vacuole

Extracellular digestion

Gastrovascular cavity

Alimentary canal

Basic parts of alimentary canal

Roles of mouth and stomach in digestion