Biology 125 Final

What type of circulatory system do acoelomates have?

No actual circulatory system, instead the gastrovascular cavity acts as a substitute.

What kind of organisms exhibit acoelomate circulation?

Cnidarians and flatworms.

What is the circulatory system derived from?

The coelum.

What type of circulatory system do pseudocoelomates have?

No actual circulatory system, instead the fluid filled cavity moves nutrients and waste.

What type of circulatory system do eucoelomates have?

The typical circulatory system, also referred to as the Hemal system.

What are the characteristics of a Hemal System?

A circulatory fluid (like blood or hemolymph), a muscular pump that uses metabolic rate to raise the hydrostatic pressure of the blood, and the use of tubes for transport.

What are the characteristics of an open circulatory system?

No capillaries, open ended vessels which lead to sinuses, the disconnect between heartrate and transport rate, and the exchange between hemolymph and cells.

What kinds of organisms exhibit an open circulatory system?

Arthropods and molluscs.

What are the characteristics of a closed circulatory system?

Having two fluids (blood or lymph), arteries that branch into capillaries, the separation between blood and interstitial fluid

How do open circulatory systems work?

The coelum has been replaced hemocoel that surrounds major organs. There are no capillaries, and when the heart contracts, the ostia close. When the heart relaxes, ostia open and hemolymph is drawn through the ostia, which passes through arteries into the hemocoel. The hemolymph then travels to the nervous system and muscles.

What is the pathway of an open circulatory system?

Heart → Arteries → Tissues → Lacunae (sinuses/hemocoel) → book lungs → heart

What is the disadvantage of an open circulatory system?

There is no system for shunting, thus it is difficult to maintain pressure.

How do closed circulatory systems work?

They utilize a high rate of sustained oxygen through arteries that are built to withstand high pressure. When the heart contracts, pressure goes up, and blood shoots into the arteries which expand. When the heart relaxes, the arteries shrink and blood can be let out. The arteries branch to the arterioles, which go to capillaries. Capillaries are extremely small, and converge into venules, which then converge to veins.

What is the purpose of valves in the veins?

They prevent backflow.

What is a vertebrates circulatory system referred to as?

The cardiovascular system.

What is the advantage of a closed circulatory system?

The capillaries can provide shunting by contracting a layer of smooth muscle, which limit blood flow to capillaries.

What is the law of continuity?

It states that liquid flow will be slower through a larger tube.

Where is blood at the highest pressure?

At the artery.

What is the top part of a blood pressure reading?

The systolic blood pressure, which is the contraction of the heart.

What is the bottom part of a blood pressure reading?

The diastolic blood pressure, which is the relaxtion of the heart.

What is the setup of a 2 chambered heart, and who has this?

1 atria, and 1 ventricle. Fish have this.

What is the setup of a 3 chambered heart and who has this?

2 atria and 1 ventricle, reptiles have this.

What is the setup of a 4 chambered heart?

2 atria and 2 ventircles, mammals and birds have this.

Who are 4 chambered hearts necessary for?

Endotherms.

Be able to label the heart.

What is the flow of blood in a circulatory system with a 4 chambered heart?

Blood returns to the right side → the lower systemic through the inferior vena cava, and the upper systemic through the superior vena cava → right atrium → right ventricle through tricuspid valve → through the semilunar valve into left and right pulmonary arteries → to right and left lungs to become oxygenated → back to pulmonary veins → to the left atrium → through mitral valve to the left ventricle → to the aorta through the semilunar valve → blood is distributed throughout the body

How do heart contractions work?

Striated cardiac muscles cells have individual rates of contractions.

What is the double circulatory system?

Blood passing through the heart twice per circuit.

Why is double circulation advantageous?

It ensures the struct separation between deoxygenated blood and oxygenated blood, ensuring that the body always has a dedicated supply of oxygen.

Where do arteries carry blood?

Away from the heart.

Where do veins carry blood?

Towards the heart.

What are lymph vessels?

Tubes that carry lymph through the body to lymph nodes and back to veins.

What is lymph?

A fluid made of white blood cells, especially lymphocytes, which attack bacteria in the blood and body tissues.

How is the rhythm of the heart controlled?

The sinoatrial node in the right ventricle generates an electrical impulse that travels to the left atria into the atrioventricular node. The AV node delays the electrical signal, which ensures the atria have enough time to fully contract and empty their blood into the ventricles. Then, the electrical signal travels to the Bundle of His and Purkinje Fbres to spread the impulse throughout the ventricles, causing them to contract and pump blood out of the heart.

What is a heart murmur?

Blowing, whooshing, or rasping caused by turbulent blood through the heart valves. Some heart murmurs may be a sign of a serious heart condition.

How is blood pressure measured?

With a sphygmomanometer. When the cuff inflates, it compresses the brachial artery, temporarily stopping blood flow. When it deflates, the blood flows again, creating a turbulent flow that are heard with a stethoscope. The first sound corresponds to the systolic blood pressure, and the point at which the sounds stop are the diastolic pressure.

What is the ideal blood pressure?

120mmHg/80mmHg

What are the components of blood?

Water, nutrients, waste, hormones, electrolytes, and plasma proteins.

What are erythrocytes?

Red blood cells, they transport oxygen and carbon dioxide.

What are leukocytes?

White blood cells, which are for defense and immunity.

What are platelets?

Cells within the blood that aid with blood clotting.

How are erythrocyte levels maintained?

Erythropoietin targets bone marrow to increase the production of erythrocytes.

What is an ischemic stroke?

A stroke that occurs when there is a blockage or obstruction in a blood vessel supplying blood to the brain. They are the main type of stroke. They can be thrombotic or embolic.

What is a thrombotic stroke?

A thrombus forms within an artery supplying blood to the brain, blocking blood flow.

What is an embolic stroke?

A stroke where a blood clot is formed and travels to the brain where it becomes lodged in a smaller artery.

What is a hemorrhagic stroke?

A stroke that occurs when a weakened blood vessel in the brain ruptures and bleeds into surrounding brain tissues, creating pressure on the brain and damaging nearby cells, depriving them of oxygen and nutrients.

What are the advantages of asexual reproduction?

It can produce many offspring in a short amount of time, it can depend on the successful genotypes, and reduce heterozygousity.

What are the 5 main types of asexual reproduction?

Binary fission, budding, fragmentation, propagation, and parthenogenesis.

What is binary fission? Who does it?

Bacteria and protists use it. The parent cell divides into two identical daughter cells, each containing a copy of the parent cells genetic material.

What is budding? Who does it?

Cnidaria, fungi, and some plants do budding. It works as a small outgrowth on a parent organism that eventually detaches and develops into a new, genetically identical individual.

What is fragmentation? Who does it?

Many plants and some animals (like sea stars) do fragmentation. It occurs when an organism breaks into several pieces, and each piece can develop into a new individual.

What is vegetative propagation? Who does it?

Found in plants, new individuals develop from vegetative parts of the parent plant like the stems, roots, or leaves.

What is parthenogenesis? Who does it?

It occurs in some invertebrates, and is a type of sexual reproduction where offspring develop from unfertilized eggs.

What are the advantages of sexual reproduction?

It increases genetic variation, and is beneficial in unstable environments.

What is heterogametic? How does this impact gamete production?

Male in an X-Y system, having two different sex chromosomes. Gametes can have different sexes.

What is homogametic?

Female in an X-Y system, have the same two sex chromosomes. Gametes will all have the same sex.

In a W-Z system, what impacts the offspring sex?

The female gamete, as they are heterogametic..

In an X-Y system, what impacts the offspring sex?

The male gamete, as they are heterogametic.

What is haplodiploisism?

Two sexes having different ploidy. The females are diploids and the males are haploid.

Why are males needed?

For sexual reproduction (sometimes).

What is the two-fold cost of males?

If offspring are produced at a 50:50 sex ratio, the females will be able to directly create offspring while the males will not. Therefore, there will be less grandchildren with a male offspring.

What is bimodality?

The mix of sexual and asexual reproduction.

Explain myxis.

Mictic stimulation causes a 2N amictic female to turn into a 2N mictic female which produces 1N eggs. 1N males will fertilize the eggs, which become dormant until conditions have been favourable. They then develop into amictic females which can produce 2N eggs to continue reproduction until a mictic stimulation is provided.

What is monoecious?

There are no sexes, all individuals of a species are the same.

What is dioecious?

There are two or more sexes in a species.

What is gonochorism?

For any individual at any given time, it is either one sex or the other. It cannot be both.

What is dimorphism?

The systematic difference between individuals of a different sex in the same species.

What is hermaphroditism?

An individual that has both male and female gonads.

What is sequential hermaphroditism?

Having female gonads at one time and male gonads at another.

What is synchronous hermaphroditism?

Having both female and male gonads at the same time.

What is atoke?

A morph incapable of sexual reproduction.

What is epitoke?

Morphs capable of sexual reproduction.

Describe spider sex.

They are dioecious.

What are the function of the pedipalps in spiders?

They are the male gonad which is used to transfer sperm.

What is the function of the epigynum in spiders?

The female genital structure.

What are spermatheca?

A receptacle which stores sperm after mating.

What are the courtship displays of spiders?

Males wave the pedipalps.

Describe sexual cannibalism in spiders?

Sometimes, a female will kill and eat a male before, during, or after copulation either for sustenance or to keep reproductive options open.

What is ovipary?

The female produces a nutritionally independent egg which gets laid.

What is ovovivipary?

A nutritionally independent egg is produced but is kept in the mothers body, who eventually gives live birth.

What is vivipary?

Offspring grow and develop in the womb and are birthed live.

What is a cloaca?

An opening for the urinary, excretory, and reproductive let-out.

What are hemipenes?

A double wielded penis.

What are intromittent organs?

Structures used for entering the female genitalia to deposit sperm.

What organisms typically have bifurcated penii?

Marsupials.

What do leydig cells do?

Produce testosterone or androgens.

What do prostaglandins do?

They are a pheromone which signals to the female which thins the cervical walls and causes uterine contractions.

What does the prostate do?

It produces anticoagulant enzymes and citrate.

Label the male reproductive system.

Label the female reproductive system.

What is GnRH?

It is secreted by the hypothalamus, targeting the anterior pituitary, causing it to release primary gonadotropins.

What are the primary gonadotropins?

LH and FSH.

What does LH do in males?

Stimulates testosterone production.

What does FSH do in males?

Stimulates production of sperm.

What does LH target in males?

The leydig cells.

Where are the sperm produced in males?

The germ cells within the sertoli cells.

What do sertoli cells do?

They get stimulated by FSH and androgens, causing them to release inhibin and activins.

What do inhibins and activins do?

They regulate the production of FSH.

What are androgens responsible for?

Primary and secondary sex characteristics.

What happens in the uterine cycle?

The endometrium is built and shed in some mammals.