Lymphoid & Epithelial structures

Question 1

which two types of leukocytes are found in lymph nodes

Answer 1

Lymphocytes & macrophages

Question 2

what are the structures that lymph flows as it enters and then leaves a lymph node

Answer 2

• The subcapsular sinus drains to the trabecular sinuses
• The trabecular sinuses empty into the medullary
  sinuses
• The lymph flows out of the medullary sinuses via the
  efferent lymph vessels
• The concave side of the lymph node is called the hilus

Question 3

what is the main cell type in germinal centers of lymph nodes?

Answer 3

B cells

Question 4

which type of white blood cells are most common in the outer (superficial) cortex; the deeper (paracortex) cortex; the medulla?

Answer 4

• Outer (superficial) cortex:
  o B cells
• Depper (paracortex) cortex:
  o T lymphocytes
• Medulla:
  o Plasma cells
  o Macrophages
  o B cells

Question 5

What three lymph nodes drain the head?

Answer 5

• Parotid lymphocenter
• Mandibular lympyhocenter
• Retropharyngeal lymphocenter

Question 6

which lymph node drains the first three mammary glands in the dog

Answer 6

axillary lymph node

Question 7

which lymph nodes drain the udder of a cow

Answer 7

superficial inguinal lymph nodes

Question 8

which structures are drained by the thoracic duct

Answer 8

Deep cervical lymph nodes

a. Along the trachea
b. Drains the deep/ventral structures of the neck to
the thoracic duct on the left side or the lymphatic
duct on the right

Question 9

which structures are drained by the right lymphatic duct

Answer 9

Right and left tracheal (jugular) trunks

a. Travel along the trachea and drain the lymph nodes
of the head/neck
b. Empty into the thoracic duct on the left side, the
right lymphatic duct or the vessels of the thoracic
inlet

Question 10

what structures drain into the visceral trunk (3 lymphocenters)

Answer 10

Drains the celiac, cranial and caudal mesenteric lymphocenters to the cisterna chyli

Question 11

what side of the body is the spleen on?

Answer 11

left

Question 12

what is an ellipsoid? What is another name for it?

Answer 12

Sheathed capillaries aka “ellipsoid”

• Surrounded by open-filled spaces of the splenic cord
• Accumulations by B lymphocytes & macrophages

Question 13

what specific site of the spleen does erythrocyte phagocytosis occur?

Answer 13

splenic cords

Question 14

what branch of the aorta supplies the spleen?

Answer 14

splenic artery

Question 15

difference between red pulp and white pulp of the spleen

Answer 15

Red pulp:
- Makes up the bulk of the spleen

White pulp:
- Lymphatic tissue
- Forms nodules and sheaths of lymphocytes around
arteries and arterioles

Question 16

marginal zone

Answer 16

• Adjacent to the pulp
• Most blood enters the red pulp in the marginal zone

Question 17

which organ in the lymphoid system filters blood

Answer 17

spleen

Question 18

organ is the primary lymphatic organ of mammals?

Answer 18

thymus

Question 19

what is the main type of lymphocyte found in germinal centers? What is produced by germinal centers?

Answer 19

• B-lymphocytes are the main lymphocyte found in germinal centers
• Antibody secreting plasma cells & memory B cells

Question 20

Do germinal centers form in the thymus?

Answer 20

NO

Question 21

what are the three principle cell types found in the thymus?

Answer 21

• Thymocytes
• Macrophages
• Epithelio-reticular cells

Question 22

what are Hassal’s corpuscles? What organ are they found in?

Answer 22

Hassal’s corpuscles: concentric mass of epithelial cells

• Only present in mammals
• Located in the thymus

Question 23

What are the 5 layers of stratified squamous epithelium?

Answer 23

• Stratum corneum (horned layer)
• Stratum lucidum (clear layer)
• Stratum granulosum (grainy layer)
• Stratum spinosum (spiny layer)
• Stratum basale (basal layer)

Question 24

what are the 2 layers of skin? How are they different?

Answer 24

Epidermis & dermis

• The epidermis is the outer layer of the skin and contains no blood cells or nerves
• The dermis is the inner layer of the skin and contains blood vessels, lymph vessels, nerves, glands, hair follicles, and muscle fibers

Question 25

What are the 5 layers of epidermis (in the skin)? Know their key features

Question 26

what are the 2 main types of dermal glands? Which one are mammary glands derived from?

Answer 26

- sweat glands and sebaceous glands o mammary glands are derived from sweat glands

Question 27

what are the 2 types of sweat glands, and how are they different?

Answer 27

- Eccrine sweat gland: o Small, widely distributed glands o Mechanism for cooling - Apocrine sweat gland: o Larger o Oily and foamy secretions o Most common in the groin, axilla and scrotum of dogs and cats o Most numerous in the horse o This is the most common type of sweat gland in domestic animals

Question 28

what are the 5 types of sensory receptors in the dermis of the skin?

Answer 28

- Merkel cells- respond to very light pressure o Found in small numbers near the stratum basale - Meissner’s corpuscles (tactile corpuscles) are sensitive to touch and are found in delicate areas such as the lips and fingertips (2) - Pacinian corpuscles detect pressure, vibrations o Lamellated o Rapidly adapting - Ruffini corpuscles o Slowly adapting o Stretch (4) - Free nerve endings sense pain, heat and cold, as well as touch (1) o Rapidly adapting

Question 29

what are the three parts of a hair (cross section).

Answer 29

- Outer cuticle: o single layer of flat keratinized cells - Cortex: o compact dead cell layer under the cuticle - Medulla: o central region of the shaft, cuboidal or flat cells

Question 30

what is the difference between wool and hair

Answer 30

- Wool (compound follicle): o several hairs emerge from a single opening o Found in dog, cat, sheep (wool growing areas) o Consists of a long principal (guard) hair and a number of smaller (wool) hairs, little medulla - Hair ((Single (simple) follicle)): o one hair emerges from a single opening o Found in horse, cattle, pig and sheep

Question 31

How many teats are on each quarter (normally)?

Answer 31

4 depending on species

Question 32

each species, know how many teats there are and what location (thoraco, abdomino, inguinal) they are in.

Answer 32

- Bitch: 10 (thoracoabdominoinguinal) - Queen: 8 (thoracoabdominal) - Sow: 10-18 (Thoracoabdominoinguinal) - Goat/sheep: 2 (inguinal) - Mare: 2 (inguinal)

Question 33

what are 5 components of the suspensory system of the bovine udder

Answer 33

- Skin/superficial fascia - 4-quarter attachment o Coarse cord like tissue - Sub pelvic tendon - Lateral suspensory ligament o Superficial & deep - Median suspensory ligament o (most important)

Question 34

where, specifically, is milk produced

Answer 34

produced in the alveoli

Question 35

what are the 4 lymph nodes that drain the bovine udder

Answer 35

- subiliac lymph node - mammary superficial inguinal lymph node - ischial lymph node - deep inguinal lymph node

Question 36

difference between hypsodont and brachydont teeth. Know which animals have which?

Answer 36

Brachydont teeth: (low-crowned) - the simple teeth of man, carnivores, pig, ruminant incisors and horse deciduous incisors. - They consist of a crown, neck, and root. Hypsodont teeth: - the teeth having no distinct neck, as seen in all permanent horse teeth, the ruminant cheek teeth, and the tusks of pigs. - Apart from the horse's canine teeth, they continue to erupt throughout life.

Question 37

three substances that compose teeth, and their location in brachydont teeth and hypsodont teeth

Answer 37

- Cementum: a thin, bone-like covering o Low-crowned (brachydont) teeth:  the cementum covers the root only. o High-crowned (hypsodont) teeth:  covers the entire tooth, superficial to the enamel - Enamel: the hardest substance in the body o Densely calcified tissue; acellualar o Low-crowned (brachydont) teeth:  the enamel covers only the crown. o High-crowned (hypsodont) teeth:  enamel envelops the body (crown & body), but not the root. - Dentin: o a hard substance similar to bone forming the bulk of the tooth and surrounding the pulp cavity. o Calcified, yet collagen-rich

Question 38

different types of teeth (e.g. incisor, etc.)

Answer 38

- Incisors - Canines - Premolars - molars

Question 39

Know the directional terms used to describe the surfaces of teeth

Question 40

when Galvayne’s groove first appears in the equine mouth?

Answer 40

Galvayne’s groove appears around age 10yrs old in the equine mouth

Question 41

Memorize the dental formula of the dog and horse (permanent) and dog (deciduous)

Answer 41

dental formula (HORSE): permanent- 2(I 3/3 C 1(0)/1(0) P 3(4)/3 M) = 36-42 dental formula (DOG): deciduous- 2(I 3/3 C 1/1 P 3/3)= 28

Question 42

Arrector pili

Answer 42

Smooth muscle fibers that can contract to pull the hair perpendicular to the skin surface by the nervous system in times of stress or cold

Question 43

Teat cistern

Answer 43

“Teat sinus”- the large milk storage cavity within the teat and the glandular body

Question 44

Gland cistern

Answer 44

“Udder”

Question 45

Intermammary groove

Answer 45

external groove separating the two halves of the udder

Question 46

Streak canal

Answer 46

“Teat canal” * duct leading from the teat sinus to the teat opening * stratified squamous epithelium * cells produce a sebaceous plug in the teat canal

Question 47

White line

Question 48

Stratum externum of hoof

Question 49

Dental cup

Question 50

Dental star

Answer 50

pulp cavity; first appears ~ 8 y

Question 51

PULP

Answer 51

the soft tissue filling the pulp cavity, including sensory nerves, arteries, veins, lymphatics, and primitive connective tissue

Question 52

CUSP

Answer 52

the individual bumps on the occlusal (chewing) surface of teeth

Question 53

alveoli

Answer 53

the bony sockets of the incisive, mandible, and maxillary bones in which the root" of teeth are embedded.