Life 103 Final Exam

1. Circulation:

a. Structure/Function of open vs. closed circulatory systems

-The circulatory system connects the fluid that surrounds cells with the organs that exchange gases, absorb nutrients, and dispose of wastes

-Blood enters through an atrium and is pumped out through a ventricle

-In an open circulatory system, circulatory fluid called hemolymph bathes the organs directly

-In a closed circulatory system, blood is confined to vessels and is distinct from the interstitial fluid

b. Structure/Blood Flow in single vs. double circulation

-In single circulation, blood leaving the heart passes through two capillary beds

before returning (Bony fish and sharks)

-In double circulation blood flows through two pathways: the pulmonary circulation (where blood is oxygenated in the lungs) and the systemic circulation (where oxygenated blood is pumped to the rest of the body). These animals have a four chambered heart (reptiles and mammals).

-SRPLS: systemic, right, pulmonary, left, systemic

c. Structure/Function of arteries/veins/capillaries

-Arteries carry blood away from the heart to capillaries. They are thicker than veins to accommodate higher blood pressure

-Veins carry blood from capillaries to the heart

-Capillaries are the site of chemical exchange. They are super thin, but have a large cross section area. Blood flow here is super slow to allow chemicals to exchange. 

-Lymph is the fluid lost by capillaries.

-Lymph nodes filter lymph, and become swollen and tender when fighting infection

2. Gas Exchange:

a. Structure/Function of respiratory systems in select animals

-Gas exchange supplies O2 for cellular respiration and disposes of CO2

-Gasses diffuse from high partial pressure to low partial pressure

-In birds, air flows only in one direction, as it takes less energy

b. Respiratory Surfaces (skin vs. gills vs. trachea vs. lungs)

-In the lungs, the blood loads O2 and unloads CO2

-Gas exchange takes place in the alveoli of the lungs.

- Mammals use negative pressure breathing, which pulls air into the lungsWhen the diaphragm contracts, the lung volume increases

-Gills are outfoldings of the body that create a large surface area for gas exchange. They use a countercurrent exchange system where Blood flows in the opposite direction to water passing over the gills. Blood is always less saturated with O2 than the water it meets.

-The tracheal system of insects consists of a network of branching tubes throughout the body. These tubes supply O2 to the body, and are separate from the circulatory system. 

-In the alveoli, O2 diffuses into the blood and CO2 diffuses into the air. In tissue capillaries, partial pressure gradients favor diffusion of O2 into the interstitial fluids and CO2 into the blood.

3. Immune System:

a. Innate vs. Adaptive Immunity

-Innate immunity is the body's natural, non-specific first line of defense against infection, present from birth

-Adaptive immunity is a specialized part of the immune system that provides long-lasting, specific protection against pathogens and can remember past infections

-Antigens are substances that can elicit a response from a B or T cell (pathogen).

-Plasma cells are effector cells that secrete antibodies to immediately attack a pathogen

-Immunological memory: The first exposure to a specific antigen represents the primary immune response

i. Examples of innate & adaptive defenses

-Innate: skin, mucous membranes, and inflammatory response (Enhanced blood flow to the site helps deliver antimicrobial peptides). 

-The digestive system is protected by a chitin-based barrier and lysozyme. Hemocytes to career out phagocytosis

-Adaptive: Antibodies and cytotoxic T cells. 

ii. Advantages of innate vs. adaptive immunity

b. Activation of & Responses of B vs. T cells

-Lymphocytes that mature in the thymus above the heart are called T cells

-Those that mature in bone marrow are called B cells. They have receptors known as antibodies that mark specific antigens for destruction.

-In the humoral immune response antibodies help neutralize or eliminate toxins and pathogens in the blood and lymph (plasma cells)

-In the cell-mediated immune response specialized T cells destroy infected host cells. Cytotoxic T cells use toxic proteins to kill cells

4. Osmoregulation/Excretion:

a. Osmoconformers vs. Osmoregulators

-Osmoregulation controls solute concentrations and fluid loss through a concentration gradient

-Osmoregulators expend energy to control water uptake and loss

-Osmoconformers are isoosmotic with their surroundings and do not regulate their osmolarity

b. Osmoregulation in marine, freshwater, & land animals

-Bony marine fish balance water loss by drinking large amounts of seawater and eliminating the ingested salts

-Freshwater fish lose salts through diffusion: drinking almost no water and excreting large amounts of dilute urine

-Land animals regulate water loss by body coverings such as skin or exoskeletons

c. Forms of nitrogenous wastes

-Waste is nitrogenous breakdown of proteins and nucleic acids

-Animals excrete nitrogenous wastes in different forms: ammonia, urea, or uric acid

-Most aquatic animals excrete ammonia as it needs lots of water to be diluted

-Mammals and amphibians excrete urea, as it is less toxic than ammonia

-Insects and reptiles excrete uric acid as it is nontoxic

d. Structure/Function of excretory systems in select animals

-Excretory systems are variations on a tubular theme

-Filtration: Filtering of body fluids

-Reabsorption: Reclaiming valuable solutes

-Secretion: Adding nonessential solutes & wastes to the filtrate

-Excretion: Processed filtrate containing nitrogenous wastes is released from the body

-Earthworms use metanephridia that collect coelomic fluid and produce dilute urine

-In insects, Malpighian tubules remove nitrogenous wastes from hemolymph & function in osmoregulation

-Kidneys, the excretory organs of vertebrates, function in both excretion and osmoregulation

-The countercurrent multiplier system involving the loop of Henle maintains a high salt concentration in the kidney

-Urine produced is isosmotic to the interstitial fluid of the inner medulla, but hyperosmotic to blood and interstitial fluids elsewhere in the body

5. Animal Reproduction:

a. Asexual vs. sexual reproduction

-Sexual reproduction: the creation of an offspring by fusion of a male gamete (sperm) and female gamete (egg) to form a zygote

-Sexual reproduction halves the number of individuals that can have offspring

-Asexual reproduction is creation of offspring without the fusion of egg and sperm

i. Examples

-Budding: is a form of asexual reproduction where a new individual develops as an outgrowth or bud from the parent organism. Found only in invertebrates

-Fission: is the separation of a parent tonto two identical offspring

-Fragmentation: Is breaking of the body into pieces, some or all of which develop into adults. Must be accompanied with regeneration

-Parthenogenesis: is the development of a new individual from an unfertilized egg

ii. Benefits/Drawbacks

-Sexual reproduction produces genetic variability, which increases survival rates in extreme environmental changes

-Asexual reproduction is expected to be most advantageous in stable, favorable environments

b. Internal vs. external fertilization

-In external fertilization, eggs shed by the female are fertilized by sperm in the external environment

-In internal fertilization, sperm are deposited in or near the female reproductive tract, and fertilization occurs within the tract

c. Production and delivery of gametes

-To reproduce sexually, animals must produce gametes

-Gametogenesis is the production of gametes

-Spermatogenesis, the formation of sperm