6.1 Amphibians, Reptiles, Fish Flashcards
What is an ectotherm?
Derive energy from an external heat source
What kind of heart do most reptiles have?
Three-chambered heart (2 atria, 1 ventricle)
Ventricle split into three parts (Cavum venosum, Cavum pulmonale, Cavum arteriosum)
What is a poikilotherm?
Temperature is the same as the environment (very variable)
What is the Preferred Optimal Temperature Zone (POTZ)?
The temp range of natural habitat for effcient metabolism (drugs, digestion, etc)
Reptile hepatic and renal blood supply
Blood from caudal 1/3 of reptile may pass via liver or kidney before returning to heart
Describe the reptilian respiratory system
No diaphragm
Breathing by active movements
Simple lungs with low SA
Describe the reptilian alimentary system
Cloaca (rectum, repro tract, urinary system)
Some have permanent teeth, others shed teeth
Some have modified salivary glands that produce venom
Describe the reptilian urinary system
Fewer nephrons that mammals
No Loop of Henle
No obvious defined cortex or medulla
Cannot produce hypertonic urine
Describe the excretion of waste products
Nitrogenous waste excreted as uric acid
Species with water access excrete urea
Aquatic species excrete ammonia
Describe reptilian repro
Some lay amniote eggs
Some give birth to live young
Male not always required
Temp often determines sex of offspring
What are the three sections of a snake?
1 - trachea, oesophagus, thymus, parathyroids, thyroid, heart, cranial lung
2 - oesophagus, lung and air sac, stomach, spleen, pancreas, gall bladder, cranial SI
3 - gonads, adrenals, kidneys, intestines, fat pads
(no urinary bladder present)
How to identify sex of a snake
Probe
Hemipeens = deeper probing = male
How to identify sex of a lizard
Femoral pores are larger in males
How to identify sex of a tortoise
Tail length
Concave under shell = male
Describe the respiratory system of fish
countercurrent exchange mechanism in gills
