chelonia Flashcards
what are the 2 types of neck retraction and give types of chelonia
cryptodira- flex vertebrae vertically - sea turtles, tortoises
pleurodira- flex vertebrae laterally - snake necked turtles ( freshwater)
what are the characteristics of the skeletal system
the carapace is not an exoskeleton but it a modified rib cage and vertebrae (T AND L). it’s comprised of fused living dermal bone covered by keratinised epidermis
what are the characteristics of the carapace
upper shell
- plates- inner bony layers
- fusion of dermal bone, ribs, thoracic and lumbar v
- scutes, outer horny layer made from keratinised scales
what are the characteristics of the skull
head is small to allow for retraction
sturdy skull and rigid upper and lower jaws
possess a horny beak which is edged with keratin
what are the characteristics of the respiratory system 6
- paired nostrils
- trachea- protected by glottis which is protected at rest , has complete cartilage rings
2 lungs
- spongy and occupy a large volume of the body cavity, strong trunk muscles expand and contract the lungs
no diaphragm
what are the characteristics of the inspiration and expiration
inspiration
- achieved by increasing the lung volume, which causes a decrease in lung air pressure resulting in air being sucked in
expiration
- limbs are retracted into the shell, causing an increase in soft tissue and pressure within the coelomic cavity which forces air out of the lungs
what are the characteristics of the digestive system 7
horny beak
tongue is fleshy and tightly attached
salivary glands have only mucus no digestive enzymes
stomach is spindle shaped and simple
herbivores with wide large intestine for microbial digestion
have a caecum
passage of food is slow allowing maximum absorption
what are the characteristics of the cardiovascular system 4
heart lies in the midline
heart is a 3 chambered organ, 2 atria and 1 ventricle
the ventricle is partially divided by a septum to prevent mixing of o2 and deo2 blood
the blood vessels are the paired aorta
what are the characteristics of the urogential system
paired kidneys which are located causally and tightly adhered to the ventral surface of inside of carapace
2 ureters which empty into urogential sinus (urodeum), ureters also connect with bladder
the bladder is a large bilobed structure with thin walls, its capable to réabsorption of water and acts as a buoyancy aid and can reabsorb some sodium in aquatic species
what are the characteristics of the reproductive system
males -
only have 1 penis which lies in central aspect of the cloaca at rest. when it’s engoreged it is projected through the vent and curves cranially
females-
fertile eggs can be carried for 4wks to 4 yrs
sperm can be stored for long periods too
what are the reproductive characteristics
sexually maturity is linked to size
sexual dimorphism is the most noticeable difference are tail length and width and shell shape
tropical species have larger males
temperature european species have larger females
what are the characteristics of the senses 5
good colour vision
scaled eyelids
no external ear
marine species have good vision in and out of water
have jacobsons organ
what are the defence mechanism
very fast and nasty bite
