Lymphoreticular cell biology Flashcards
(65 cards)
1
Q
Rabbit circulatory volume
A
- approx 55-70ml/kg
2
Q
How much blood can you take from up a rabbit?
A
- 10% blood volume (/1% BW)
- 5.5-7ml/kg (but unlikely to need more than 2ml)
3
Q
Rabbit blood tubes
A
- EDTA for haematology
- serum or lithium heparin for biochemistry
- fluoride oxalate for glucose
- 2 fresh blood smears
4
Q
Locations for rabbit venipuncture
A
- jugular
- cephalic
- saphenous
- marginal ear vein (not middle artery)
5
Q
Risk of rabbit venipuncture from the marginal ear vein
A
- can cause pinna neurosis if use a rough technique or repeated sampling
- need to apply pressure for longer afterwards to avoid haematomas
6
Q
Jugular vein sampling in rabbits
A
- similar technique to cat
- dewlap can get in the way
- restraint may inhibit respiration
- much faster bleeding time cf ear vein
- sternal wide forelimbs extended
- if get haematoma or thrombosis after sampling it can block the vein -> causes oedema of the eye and potentially loss of vision
- beware of hyperextension of the neck also -> may compress and block the airway
- always avoid in dyspneic rabbits
7
Q
Cephalic and saphenous venipuncture in rabbits
A
- similar technique to cat
- ensure proper restraint
- common for cephalic vein to be more branched, so clip and check edges to see if better area
- saphenous -> vein raised just past the stifle, access vein just as it passes the hock
8
Q
Guinea pig circulatory volume
A
- approx 70-75ml/kg
9
Q
How much blood can you take from a guinea pig?
A
- 1% BW / 10% blood volume
- 7-7.5ml/kg
- limit blood sample size if anaemic or in circulatory shock
- rarely need more than 2ml
10
Q
Locations for guinea pig venipuncture
A
- cephalic vein (situated more lateral)
- cranial vena cava (most useful for large blood draws)
11
Q
Average blood volume of rats, mice, gerbils & hamsters
A
- 60-70ml/kg
12
Q
How much blood can you take from a rat/mouse/gerbil/hamster?
A
- 1% BW / 10% blood volume
13
Q
Locations for venipuncture in rats/mice/gerbils/hamsters
A
- lateral tail vein (warm for vasodilation, avoid in gerbils to avoid sloughing)
- lateral saphenous vein
- cranial vena cava
- ventral tail artery (can be used in rats, it runs just in the ventral midline but has a higher risk of haematoma - due to higher pressure as an artery
14
Q
Ferret blood volume
A
- 50-70ml/kg
15
Q
Locations for ferret venipuncture
A
- jugular vein (more lateral compared to cat)
- cranial vena cava
(- avoid the tail vein - very painful)
16
Q
Locations for hedgehog venipuncture
A
- cranial vena cava
- jugular vein (hard to visualise due to thick skin, ramus of mandible and point of shoulder for landmarks)
- femoral vein (inside hind leg as it runs across the stifle)
17
Q
Method of cranial vena cava venipuncture
A
- usually in many smaller species
- potential for severe complications if performed incorrectly
- in some species (e.g. GP, hedgehog) the heart lies very close to the sample site
- thoracic pathology may change normal anatomy (radiograph 1st helps)
- anaesthesia is essential
- pt in dorsal recumbency, head extended, forelimbs retracted caudally
- 25G, 0.5” needle
- needle placed at the notch where 1st rib meets the manubrium
- advance toward the contra-lateral hindlimb
- approx 30 degree angle until blood flash
18
Q
Reptile venopuncture
A
- most veins aren’t visible, so use landmarks and feel
- the lymphatic system is closely associated with blood vessels which may lead to contamination of blood samples (affects PCV and some biochem)
- bp low and blood draws slowly
- as with other spp, always do a fresh blood smear
- may need to hospitalise and give fluid (e.g. reptoboost bath) to allow sampling
- skin often heavily contaminated so ensure thorough skin prep
19
Q
Reptile blood tubes
A
- EDTA tends to haemolyse reptile RBCs
- lithium heparin is anticoagulant of choice
- 2 good quality fresh smears
20
Q
Why is haematology usually perfumed manually in reptiles?
A
- automated techniques are made difficult due to nucleated RBCs
21
Q
Reptile circulating blood volume (& collection volume)
A
- approx 5-8% BW
- may collect up to 10% (i.e. 5-8ml/kg)
- but many reptiles present in poor to very poor health and are often anaemic
- therefore, often take 1/2 this amount
- rarely require more than 2ml
22
Q
Lizard venipuncture sites
A
- ventral coccygeal vein
- ventral abdominal vein
- jugular vein
23
Q
Ventral coccygeal vein sampling in lizards
A
- most useful
- entry approx 1/3rd down the tail to avoid hemipenes and anal glands
- ventral or lateral approach may be used
24
Q
Ventral abdominal vein sampling in lizards
A
- may be visualised in some spp
- difficult to prevent haematoma so use as small a needle as possible
25
jugular vein sampling in lizards
- useful in large longer-necked spp e.g. Monitor lizards
- blind approach along imaginary line from dorsal ear to shoulder
- often quite superficial
- risk of lymphatic contamination is lower at this site
- potential damage to carotid artery and vagus nerve
26
Snake venipuncture sites
- ventral coccygeal vein
- heart
- palatine veins
27
Ventral coccygeal vein sampling in snakes
- similar approach to lizards
- difficult in small snakes
- tail end held in dorsal recumbency
28
Heart blood sampling in snakes
- dorsal recumbency
- heart located visually, with doppler or US
- stabilise heart between finger and thumb
- needle central ventral midline at a 30 degree angle in a cranial direction (aim for caudal point of ventricle)
- GA required
- smallest possible needle
- can't use this method in lizards as can't stabilise the heart like you can in snakes
- taken directly from the ventricle
29
Palatine vein sampling in snakes
- prone to haematoma formation
- large, anaesthetised snakes only
- rarely used
30
Chelonia venipuncture sites
- jugular vein
- sub-carapacial vein
- dorsal coccygeal vein
31
Jugular vein sampling in Chelonia
- along line from dorsal ear scale to shoulder
- tends to be superficial
- visible in some spp
- lymph contamination least likely
- carotid artery deeper and more ventral
- head extended to the side, or insert the needle parallel to the head
32
Sub-carapacial vein sampling in Chelonia
- entry point craniodorsal midline where skin joints carapace
- aim for point at junction of 1st & 2nd vertebral scute on midline
- may need to bend needle slightly
- head may be retracted or extended (i.e doesn't need to be extended out of the shell)
33
Dorsal coccygeal vein sampling in Chelonia
- often superficial
- aim as far cranial as possible
- often lymph contaminated
34
Rabbit erythrocytes
- anisocytosis and polychromasia is a common, normal finding
- may be due to shorter erythrocyte lifespan (57-67d)
35
Rabbit WBCs
- heterophiles instead of neutrophils
- heterophiles have granular cytoplasm and may be listen for eosinophils
- basophils are present quite commonly
- lymphocytes, eosinophils and monocytes similar to dog/cat
36
Guinea pig blood cells
- Kurloff cell = produced by the thymus under oestrogen stimulation, resembles lymphocyte with round to oval inclusion, thought to have a similar role to lymphocytes (producing antibodies, attacking unknown cells)
- neutrophil most abundant cell
37
Ferret blood cells
- neutrophils: contain small, pale-red granules
- eosinophil: granules rounded and bright red
- generally have higher HCT, HB and RBC counts
- WBCc generally quite low (3-4x10^9)
- ferrets appear to have no blood groups
38
reptile erythrocytes and thrombocytes
- both cell types are nucleated
- similar function to mammals
- PCV 20-40% in most species
- erythrocyte life span up to 800d in some spp
- polychromasia and reticulocytosis low (<1%)
39
Reptile heterophils
- predominant cell type
- equivalent to neutrophil
- intracytoplapmic fusiform granules
- increase in summer, decrease during hibernation
- heterophobia = infection, inflammation, stress
- heteropaenia = chronic stress/dz, severe infection
- will show signs of toxic changes in response to severe illness (e.g. inflammatory dz that affects bone marrow)
40
Reptile lymphocytes
- morphology very similar to mammals
- lymphocytes generally lowest in winter
- lymphopaenia = malnutrition, stress, immunosuppression, poor husbandry
- lymphocytosis = inflammation, parasitic & viral dz, wound healing, ecdysis
41
Reptile eosinophils & basophils
- similar morphology to mammals
- eosinophils generally lower in summer
- eosinophilia = parasites and inflammation
- basophils minimal seasonal change
- basophilia = parasitic & viral dz
42
Reptile azurophils
- unique to reptiles
- similar to monocytes in mammals
- red-purple cytoplasma
- more common in snakes
- inflammatory response and carry out phagocytosis
43
Reptile monocytes & azurophils
- reptiles also have monocytes, which are similar to those of mammals
- monocytosis & azurophilia occur with inflammation and granulomatous dz
44
Risk factors of avian venipuncture
- veins are generally very superficial
- veins are very fragile and prone to haematoma formation
- post-sampling haemorrhage and haematoma formation is potentially life-threatening
45
Circulating volume of birds and collection volume
- approx 6-12% BW
- can collect up to 10% of this (6-12ml/kg)
46
Avian blood tubes
- EDTA can haemolyse RBCs in some spp (esp corvids and waterfowl)
- lithium heparin used for haem and biochem in small pts
- always make 2 good quality fresh smears
47
Why is haematology usually performed manually in birds?
- automated techniques are made difficult due to nucleated RBCs
48
What can inadequate and prolonged restraints cause in birds?
- injury to pt
- injury to handler
- possibly fatal haemorrhage
- stress
- hyperthermia
49
Sedation/GA with gas for avian venipuncture
- probably less risk than physical restrain in sick or fractious birds
- reduce haematoma formation by relieving stress and lowering bp
50
Avian restraint for venipuncture
- firmer pressure around the head and looser around the body -> reduces pressure around chest and middle
- ensure wings are restrained against the body
- for birds of prey (restraint is called casting), hoods can be useful, and ensure have restrained the legs/talons
51
Sites for avian venipuncture
- jugular vein
- ulnar/basilic vein
- medial metatarsal vein
52
Jugular vein sampling in birds
- large accessible vein
- right jugular vein usually tends to be larger
- can use in all spp
- easily visualised in most without plucking feather
- palpation and blind technique in some species (penguin, waterfowl, cranes)
- can be difficult to prevent/stop haematoma
- needle advanced cranial-caudal
53
Ulnar/basilic vein sampling in birds
- small samples in larger birds
- potential to fracture wing if performed conscious
- haematomas are common and can be severe
- runs on the inside surface of the elbow
- bird placed in dorsal recumbency
- extend the wing
- wing stabilised with thumb and forefinger
- syringe rested on thumb and advanced into vein
54
Medial metatarsal vein sampling in birds
- lateral recumbency with lower limb extended caudally
- easy to restrain in towel with feet out
- limb held by assistant similarly to dog/cat
- medial aspect, above or below joint
- light pressure bandage easily placed to prevent haematoma
- useful for poultry and waterfowl, usually visible in these spp without plucking feathers
- as the area is heavily scaled haematoma formation is much more likely
55
Avian cellular origins
1. primary lymphoid organs: Bursa of Fabricius, the thymus
2. secondary lymphoid organs: spleen, intestinal lymphoid tissue, bone marrow
56
Avian thymus
- located in the neck
- consists of 3-8 flattened, pale pink lobes lying along the neck, close to the jugular vein
- t-lymphocyte precursors are produced by stem cells in the embryonic yolk sac and bone marrow, and then develop into T-lymphocytes in the thymus
- thymus decreases in size at sexual maturity
57
Bursa of Fabricius
- unique to birds
- is a dorsal diverticulum in the proctodeum (the final part of the cloaca used for storage)
- consists of folds of lymphoid tissue
- stem cells in yolk sac produce B-lymphocyte precursors which then develop in the Bursa
- subsequently seeds other lymphoid organs with B-cells
58
Avian spleen
- situated on right side of coelom between proventriculus and ventriculus
- shape varies
- not a blood reservoir so is relatively small
- aged erythrocytes are phagocytosed
- aids in lymphopoiesis and production of antibody
59
Aivan erythrocytes
- formed in bone marrow
- nucleated
- similar function to mammals
- PCV = 35-55%
- relatively short lifespan = 25-45d
- blood loss replenished in days
- cell size varies with spp
- normal to find mild immature RBC numbers (mild polychromaisa and anisocytosis)
60
Avian thrombocytes
- similar to mammalian platelets
- originate from stem cell not megakaryocytes
- nucleated
- phagocytic functions
- clotting function weaker cf mammals
- despite higher bp, clotting still works
61
Avian heterophils
- function similar to mammalian neutrophil
- most abundant cell in most spp
- round cells with lobed basophilic nucleus
- prominent needle-shaped, oval or round cytoplasmic granules
- cytoplasm is colourless
- phagocytosis, bacteriocidal, roles in acute inflammation
- heterophobia = stress, infection
- heteropaenia = acute or severe inflammation, sepsis, viruses
62
Avian eosinophils
- normally present in low numbers
- may be elevated with tissue damage and parasitic dz and possibly some viral infections
- round cells, lobed basophilic nucleus
- cytoplasm stains clear blue
- granules are bright and tend to be round
63
Avian basophils
- slightly smaller than heterophils
- clear cytoplasm, darker granules
- nucleus non-lobed round to oval and often obscured by cytoplasmic granules
- function unknown, possible involved in acute inflammation and hypersensitivity reactions
64
Avian lymphocytes
- similar morphology to mammals
- large round nucleus with pale blue cytoplasm
- variation in size and shape
- lymphocytosis = excitement, leukaemia
- lymphopaenia = chronic stress
65
Avian monocytes
- rare in healthy birds
- similar morphology to mammals
- largest leukocyte in a normal blood smear
- little consistency in appearance
- monocytosis = chronic inflammation/infection e.g. Psittacosis, tuberculosis, aspergillosis, egg coelomitis
