Anatomy Exam 5

Cortex

nephrons are mostly localized to the cortex

Medulla

Collecting duct and loop of henle extend into this

Minor calyx, major calyx

where urine produces flow into

Renal pelvis

Where urine is collected

Bladder

the renal pelvis is a common chamber that connects to this

Ureter

What the renal pelvis is connected to the bladder with

What is the kindey’s main role?

To maintain homeostasis

Homeostasis

a constant or near constant internal environment, temp, salinity, hydration

Kidney’s two main functions

Excretion of waste and osmoregulation

Excretion of waste

• waste products of metabolism

• Sugars- Co2 and H2O

• Fats- Co2 and H2O

• Proteins- Co2, sulfates, phosphates, nitrogen

• Nucleic acids- Co2, phosphate, nitrogen

Ammontoelism

direct excretion of ammonia

• found in fish, living in water is key, bc can flush out ammonia due to it being soluble

• Doesn’t take much energy

• Flushed via gills or permeable membranes

Uricotelism

Excretion of uric acid

• Most repitles and birds

• Kidneys form uric acid whcih mixes with various salts in the cloaca to form sludge

• Little water lost

• Takes a lot of energy

Ureatelism

Excretion of urea

• Mammals

• The kidneys convert ammonia into a concentrated urea (liquid)

• Urea is less toxic than ammonia and requires less energy to form

• The water content of the urea can be modified as needed

Urinary System

Kidneys and ducts that transport urine out of the body

Reproductive System

Gonads and the ducts which carry eggs or sperm away

The Urinary System

Serve multiple roles:

Water balance

Collection and excretion of waste (Nitrogen)

Salt balance

Uriniferous Tubule

Comprised of the nephron and collecting tubule

How is the blood brought into kidneys?

Renal Arteries

How does blood flow into a bundle of capilleries called what

The glomerulus

Blood is filtered and the filtrate is collected in

the renal capsule

This filtrate passes through a series of tubules called the nephron

Proximal, intermediate, and distal tubules

Filtrate eventually into the

Collecting tubule

Renal Vein

Eventually returns to a series of veins before leaving the kidneys

What is missing in some fish?

Glomerulus and renal capsule

In mammals, what does the intermediate nephron turn into

loop of henle

Excretion Waste Sugar

CO2 and H2O

Excretion waste fats

CO2 and H2O

Proteins Waste

CO2 Sulfates, Phosphates, Nitrogen

Nucleic Acids Waste

CO2, Phosphates, Nitrogen

Variation Lungfish of elimination

Lungish- excrete ammonia in water, but urea during dry season

Variation Alligators of elimination

Can excrete ammonia or uric acid

Variation turtles of elimination

Can excrete all three

Osmoregulation

Homeostatic regulatory mechanism used to maintain concentration of water and ions

Osmolarity

Total solute concentration

Freshwater teleost nephron

PT, IS, DT, CT

Marine Teleost nephron

PT, CT

Mammal nephron

PT, IS, DT, CT

Mass Filtration

Freshwater are hypertonic to environemnt, so allowing a greate deal of water loss

Where does filtration occur

Between glomnerulus and renal capsule - called renal corpuscle

How does well differerntiated tubes help freshwater fish

They have well developed glomerulli, distall tube in particular removes important nutrients from filtrate

Why do saltwater fish remove glomerulus and renal capsule and distal tube

Reduces the initial ampuint of filtrate - dt- greater retentition without

How is filtration different from reabsorption?

Reabsorption is selective, mammals accomplish this with an extensive loop of henle

Where does most reabsorption occur

In the proximal tubule, which is covered in microvilli

How does loop of nephron help

Create of osmotic gradient within medulla by pumping out sodium

Why is distal tube incorporated into the loop of henle

To absorb more salt

What controls water permeability in the distal tube and collecting duct

Hormones

When dehydrated

Water moves across the membrane to be reabsorbed

When hydrated

The membrane is made impermeable, to allow water to be expelled

Shark

Keep high amount of urea in the blood making shark isotonic , sharks use a lot of energy to protects themselves from urea

Pronephros

Found in larval forms and some adult fish.

Mesonephros:

Found in most fish and amphibians

Metanephros

found in amniotes

Holonephros

All seperate parts of one kidney

Gatrulation

creates initial gut of animal

Neurulation

Process of forming the intial neural tube coincides with this

Three germ layers

Ectoderm, mesoderm, and endoderm

Urogenital ridge forms from what

Mesoderm

Coelom

Body cavity between alimentary canal and body wall

What arises from urogenital ridge

Nephric and genital ridges

nephric tubules

formed within nephritic ridge

Tripartite Concept

These tubules can appear in pronephros, mesonephros, or metanephros

Archineprhic Duct

Genral name for this common duct

Metanephric duct

What metanephros uses- it is the ureter

If gonads are producing sperm

archinephric duct becomes the vas deferencs

If gonads produce an ova

Mullerian duct arises and becomes basis of oviducts w archinephric duct

Funnel

Connects the eggs from ovaries

Shell Gland

Secretes albumen and mucus

Isthmus

Connectgs shell gland to uterus

Uterus

Gives nutrients to egg while held

Fallopian Tubules

Oviduct between the ovaries and uterus

Lateral vagina

Two uterus empties into a vaginal sinus split into two, reconnect at urogentical sinus- opposums

Central Vagina

Lateral vaginas are connected by this at urogenetial sinus

Duplex- Rodents, and Rabbits

Two separate uteri

Bipartite-cats, horses, and cows

Parital fused uteri

Bicronuate- dogs, elephants, marine mammals

More fused

Simplex- higher primates

Single uterus chamber

Coprodeum

Connects to intestine

Urodeum

Connected to bladder

Procotdeum

Connected to genitals,

Placenta

Nutrients and oxygen are shared with the embryo via this

pleiotropy

one gene has a wide influence over anatomical form

Homeotic genes, or master gene switch

homeotic genes control a host of secondary genes that are responsble for building parts of the anatomy

Hox gene

Genes that specify regions in an embryo

Knock-out studies

assessing the roles of various genes,

Wings and hair are examples

Müllerian ducts provide a good case study: ovaries, fallopian tubes, etc.

agenesis

absence of a body part

atresia

opening or passage of a tract is closed

Septation

Additional partitions within the organ

Mullerian Duct Formation

Occurs in the initial undifferentiated system

Mullerian Duct Regression

Occurs if testes are formed

Mullerian Duct Differentiation

The duct is differentiated into the uterus, cervix, and vagina

Mullerian Inhibiting Substance

Produced by fetal testes to regress the mullerian duct

If without, testis as well as ovaries and uterus will develop

If ova form but expressed, ducts will not develop

Persistant Mullerian Duct Syndrome (PMDS)

Testis are present and functional and retain mullerian duct,

mutation that code for MIS

mutation in genes that code for MIS receptors

HoxA control

differentiation of the mullerian duct in mice

Hoxa9-

expressed in the oviduct

Hoxa10

Expressed in the uterus

Hoxa11

Expressed in the uterus and cervix

Hoxa13

Expressed in the cervix and upper vagina, if 13 replaces 11, the uterus will become like the cervix and vagina

Hand-foot-genital syndrome

Big toes and short thumbs and duplex or bicornuate uteri

Hd mice often have undeveloped Mullerian ducts and are infertile

What arises from genital ridge

indifferent gonads - no testis or ovaries

How do germ cells work?

They form outside of the embryo and travel inwards towards the gonads, if enter medulla -testis

if enter cortex- follicles leading to ovary development