Lecture 18

Question 1

Urogenital System (2 components):

Answer 1

1. Excretory system
2. Reproductive system

Question 2

Urogenital System (Excretory System) (3):

Answer 2

1. Removes nitrogenous wastes (ammonia, urea, or uric acid) and other harmful substances
2. Controls osmosid to achieve water and salt balance
3. Organs involved: kidneys, gills, skin, part of the digestive system, salt glands

Question 3

Urogenital System (Reproductive System) (2):

Answer 3

1. Produce and release gametes, bring them together, provide nourishment to young
2. Organs involved: gonads, dict, cloaca, copulatory organs

Question 4

Developmental Origin of Kidneys (General) (3):

Answer 4

1. Development moves in sequence from anterior to posterior in three secretions with breaks in between them
2. More anterior regions usually degenerate as posterior regions become functional
3. More posterior break may not form so that two instead of three pairs of kidneys are formed in sequence

Question 5

Pronephors General (5):

Answer 5

• Segmented, usually first 4 segments
• Drained by pronepgric duct
• Appears in all vertebrates (rudimentary form), but degenerated quickly
• Functional in fiah larvae, adult hagfish and some teleosts
• In most teleosts degenerates into ‘head kidney’

Question 6

Opisthonephros/Mesonephros General (4):

Answer 6

1. Reduced segmentation
2. Drained by opisthonephric or mesonephric duct
3. In late larval and adult anamniotes (fishes and amphibians), all or most of the mesomere posterior to pronephros forms one kidney (opisthonephros)
4. Among amniotes, the middle part of the nephrogenic cord, the mesonephros, develops first, is present in fetuses, and then degenerates

Question 7

Metanephros Overview (5):

Answer 7

1. Never segmented
2. Kidney of adult amniotes
3. Most posterior part of nephrogenic cord that replaces mesonephros in development
4. Old mesonephric duct degenerates in female but persists in males to carry sperm –> vas deferens
5. Metanephric kidney is drained by a new duct (ureter)

Question 8

Nephron Components:

Answer 8

1. Renal corpiscle
2. Nephric (renal) tubule

Question 9

Functional Units of the Kidney - Nephron (2):

Answer 9

1. Glomerulus = cluster of capillaries (externall or internal)
2. Renal or Bowman’s capsule = cup-like sack that collects nitrogenous waste

Question 10

Variations in Kidney Structure:

Answer 10

Kidney structure across vertebrates depends on the osmoregularatory challenges of different environments and the type of nitrogenous waste produced

Question 11

Variations in Kidney Structure - Terrestrial Environmental Challenges:

Answer 11

Water loss through skin and lungs –> dehydrating environment

Question 12

Variations in Kidney Structure - Freshwater Environmental Challenges:

Answer 12

Water uptake, salt loss through skin and gills

Question 13

Variations in Kidney Structure - Saltwater Environmental Challenges:

Answer 13

water loss, salt uptake through skin and gills

Question 14

Gonads (General):

Answer 14

• Develop from two sources in the embryo
• Mesomere genital ridges: become supporting tissues of gonads
• Primordial germ cells - become gametes, arise from endoderm and migrate to genital ridge early in development

Question 15

Principle Urogenital Ducts (4):

Answer 15

1. Nephric ducts (pro, meso, opistho)
2. Muellerian ducts
3. Ureter
4. Accessory ducts

Question 16

Do Cyclostomes Have Sexual Ducts?

Answer 16

• No
• Eggs and sperm released directly into coelom (body cavity) and exit into cloaca by way of genital pores

Question 17

Variations of the duct system among groups are the results of:

Answer 17

The retention, loss of modification of the fetal structures

Question 18

Male Ducts - Sharks and Amphibians (2):

Answer 18

• Nephric ducts (vas deferens) carry sperm
• Accessory urinary duct carries waste

Question 19

Male Ducts - Teleosts:

Answer 19

• Nephric ducts (opisthonephric duct) carry waste
• Testicular duct carries sperm

Question 20

Male Ducts - Amniotes:

Answer 20

• Nephric ducts (vas deferens) cary sperm, ureter carries waste

Question 21

Female Ducts - Sharks and Amphibians:

Answer 21

• Opisthonephric ducts carry waste
• Oviduct (Mullerian) carries ova

Question 22

Female Ducts - Teleosts:

Answer 22

• Opisthonephric ducts carry waste
• ovarian duct (ovarian folding) carries ova

Question 23

Female Ducts - Amniotes:

Answer 23

• Ureter carries waste
• Oviduct (Muellerian) carries ova

Question 24

Reproductive Strategies of Vertebrates - Different Types (3):

Answer 24

1. Oviparity
2. Ovovivparity
3. Viviparity

Question 25

Reproductive Strategies of Vertebrates - Oviparity:

Answer 25

Eggs laid with little or no maternal development

Question 26

Reproductive Strategies of Vertebrates - Ovovivparity:

Answer 26

Embryos develop inside eggs within mother

Question 27

Reproductive Strategies of Vertebrates - Viviparity:

Answer 27

Development of live embryo inside mother

Question 28

Shark / Chondrichthyan Reproductive Strategies (female and males (4):

Answer 28

1. Fertilization generally internal 2. Male specializations - pelvic fin specialized into claspers (inserted into female during copulation; sperm runs down groove into female cloaca) 3. Femal Specializations - nidamental (shell) gland responsible for sperm storage, oocyte fertilization and egg formation 4. Some oviparous (lay an egg capsule called a mermaid's purse), some ovovivparous (eggs develop internally, give birth to live young)

Question 29

Teleost Reproductive Strategies:

Answer 29

- fertilization generally external (broadcast spawners) - Male specializations --> in the few species where fertilization is internal, the male anal fin is specialized into a gonopodium (grooved intromittent organ) Female specializations --> ovaries often fuse or only one is functional (or fails to develop)

Question 30

Amphibian Reproductive Strategies:

Answer 30

- External fertilization, internal in some salamanders via spermatophores - males specializations --> many male frogs have modifications for amplexus (grasping female during courtship) such as enlarged toe pads; tailed frogs possess tail-like extension of the cloaca for internal sperm transfer - Femals specializations --> some female salamanders have a spermatheca to store sperm

Question 31

Reptile Reproductive Strategies:

Answer 31

- Fertilization is internal via cloacal contact or intromittent organ (penis or hemipenes) - Eggs typically laid on land, sex of embryos often dependent on environment temp - Male specializations --> turtles and crocodiles possess hemipenes (in both cases, can be retracted into the body by muscles) - Female specializations --> females of some species are parthenogenic

Question 32

Avain Reproductive Strategies:

Answer 32

- Fertilization is internal via cloacal contact, rarely through intomittent organ (penis) (oviparous) - Reproductive organs for both sexes decrease in size dramatically outside breeding season (adaptation for flight) - Male specializations --> some species display cloacal (penile) swelling, others have elaborate spiraled penis - Female specializations --> many possess sprem storage tubules for delayed fertilization; typically have a single ovary; shell gland for eggshell formation

Question 33

Reproductive strategies - Placental Mammals:

Answer 33

- Fertilization is internal (placental viviparity) - Male specializations --> baculum (penis bone) present in most placental mammals; penis compared of erectile tissue (blood sinusoids) separated by sheets of connective tissue (trabeculae) - Female specializations --> absence of epipubic bone allows expansion of abdomen during pregnancy; pelvis widening to allow birth; duplex (two separate), bipartite (two fused at cervix), bicornuate (two fused) or simplex (single) uterus for development of fetus along with placenta