L01 - Snakes Flashcards
(49 cards)
1
Q
Key points of snakes general anatomy?
A
- celomic body cavity
- no movable eyelids
- scales
- legless
- ectothermic
- autotomy is uncommon in snakes
2
Q
What is the structure of their skull?
A
- most kinetic, extremely flexible and mobile bones
- they have a small cranial cavity which protects the brain and nasal cavity
3
Q
What is the structure of the snakes jaw?
A
- each half of upper and lower jaw can move indecently, allowing the mouth to open wide to swallow larger prey
- mandible and quadrate bone can pick up vibrations in the ground
- jaw has independent movement
4
Q
What is the function of the quadrate bone?
A
- allows vertical and horizontal rotation of the jaw
5
Q
Why do snakes yawn after eating?
A
- to reposition their jaws
6
Q
How many rows of teeth do snakes have?
A
- maxilla has 2 rows of teeth on each side
- mandible has 1 row of teeth on each side
7
Q
What is the structure of snakes fangs?
A
- front, rear and none, and they point backwards
- they are not used for chewing
- they are attached to the bone
- fangs are hollow, erectile or fixed
8
Q
Non-venomous snakes teeth structure?
A
- all teeth are short and hook like
- includes constrictors
9
Q
Venomous snake teeth structure?
A
- grooved fangs
- allows venom to flow along
10
Q
What is the structure of snakes vertebrae?
A
- they have an elongated body with no limbs
- all vertebrae are similar in shape and articulate with each other
- all vertebrae have ribs except the coccygeal vertebrae
11
Q
How many vertebrae do snakes have?
A
- numbers vary from 200-400
12
Q
How many ribs do snakes have?
A
- can have between 100-435 ribs
13
Q
Where are ribs not connected?
A
- they have no sternum so they are not joined to the midline
14
Q
What is the function of ribs?
A
- flexible
- protection of organs
- contribute to respiration
- attachment of muscles to aid locomotion
15
Q
What is included in vestigial limbs?
A
- pelvic girdle
- femur
16
Q
Structure of the snakes upper tract respiratory system?
A
- paired nostrils
- no hard palate or epiglottis
- strong glottis
17
Q
What is the function of the glottis?
A
- formed from cartilages to form the glottal tube
- rigid enough to hold form whilst eating
- at rest the glottis is close
- when breathing the glottis opens into the trachea
18
Q
What is the structure of snakes lower tract respiratory system?
A
- trachea has c shaped rings of cartilage
- lungs differ depending on species
- lungs are elastic
19
Q
What are the 2 types of lungs?
A
Colubrids - right lung is major and left is vestigial
Boidea - 2 lungs, 1 is smaller than the other
20
Q
What is a tracheal lung?
A
- the out-pouching of the trachea to aid when eating large prey
21
Q
What do aquatic snakes have?
A
- they have air sacs that extend to the cloaca
22
Q
Snakes basic digestive system?
A
- carnivores
- digest prey whole and cannot digest hair
- ensure preferred body temperature is met, if snake is too cold it will slow down or stop digestion
23
Q
What is the structure of snakes oral cavity?
A
- long, slender, mobile and forked tongue
- can catch odours on moist surface by flicking tongue
- contain salivary glands, released during mastication
24
Q
What are the functions of the oral cavity?
A
- olfaction
- taste
- touch
25
What is the Jacobson organ?
- forked tongue will gather airborne particles
- the tongue will return to the mouth and pass the particles to the vomeronasal organ in the mouth
- tongue is kept in constant motion
- provides directional sense of smell and taste
26
What is the structure of their oesophagus?
- highly distensible muscular tube
- enters the stomach in second third of the middle portion of the body
- difficult to differentiate from the stomach
27
What is the structure of their stomach?
- strong, elastic and tubular
- powerful digestive juices
- digests prey whole
28
What are the 3 parts of the small intestine?
- duodenum
- jejunum
- ileum
29
What is the structure of the spleen and pancreas in snakes?
- some have a splenopancreas
- spleen is adhered to the pancreas
30
Where is the liver located?
- runs from midpoint of the lungs to the caudal stomach
31
What is included in the large intestine?
- some snakes have a caecum
32
What are the 3 chambers of the cloaca?
- coprodeum
- urodeum
- proctodeum
33
What happens in the coprodeum?
- faces is discharged from the large intestine into the coprodeum
34
What happens in the urodeum?
- receives the urogenital ducts which carry urine and either eggs or sperm
35
What happens in the proctodeum?
- acts as a general collecting area for digestive and excretory wastes
- the male hemipenes open into the portion of this compartment nearest the tail
36
How does excretion occur in snakes?
- urates and faeces are passed through the same opening
37
How many chambers does there heart have?
- primitive 3 chambered heart
38
What is the cardiovascular system movement of blood?
- oxygen depleted blood is pumped into 1 atria
- oxygen rich blood from the lungs gets pumped into the other atria
- all empty into the lower common ventricle and then is circulated through the body
- blood from rear end passes through the kidneys on the way back to the heart
39
What is the structure of males reproductive system?
- 2 testes located within the body, cranial to the kidneys
- testes enlarge during the breeding season
- testes empty into deferent ducts which empties into the urodeum
- 2 hemipenes which lie inverted but evert when engorged with blood
- have barbs/spines and have a dorsal groove
40
What is the structure of females reproductive system?
- paired ovaries which lie cranial to the kidney
- the right ovary is larger and more cranial than the left
- can store sperm in the oviducts
41
What are the 3 ways female snakes reproduce?
Oviparous - produce eggs which are hatched after laid
Viviparous - live young developed within the parent
Ovoviviparous - produce eggs which are retained in parents until hatched, live offspring are born
42
What is the structure of their skin?
- scales
- keratinised outer layer of epidermis
- smooth, keeled, or granular different sized scales
- they have little to no skin glands
43
What is ecdysis?
- the shedding of the skin
- 1 to 4 times a year
- new skin forms beneath the old
- eyes cloudy during this period
- protein rich fluid is absorbed between old and new skin and then the fluid id re absorbed
44
What are their 4 methods of perception?
- infrared sensitivity
- eyesight
- vibration
- tongue
45
What is infrared sensitivity?
- pit organs infrared
- teaching of prey
46
What is snakes eyesight like?
- ranges from very poor to very good
47
Are snakes sensitive to vibration?
- highly sensitive to vibration
48
What do snakes use their tongue for?
- olfaction
- taste
- touch
49
What are snakes 2 injection sites?
Intramuscular - intercostal muscles
Intravenous - ventral coccygeal vein
