Lecture 7

Question 1

In which species is the extracranial internal carotid artery absent?

Answer 1

Cat

Ruminants (large and small)

Question 2

Identify the following vessels.

Answer 2

1 - Internal carotid artery

2 - Cerebral arterial circle

3 - Basilar artery

4 - Branch of vertebral artery

Question 3

Which four vessels can contribute to the cerebral arterial cirlce?

Answer 3

Internal carotid artery

Vertebral artery (via basilar)

Occipital artery

External carotid artery

Question 4

In addition to contributing to the cerebral arterial circle, branches off the basilar artery supply what?

Answer 4

Brain stem and cerebellum

Question 5

In animals lacking an extracranial internal carotid artery, which artery is the major supplier to the cerebral arterial circle?

Answer 5

External carotid artery

Question 6

What is the name of this structure?

Answer 6

Rete mirabile

Question 7

Where is the rete mirabile located?

Answer 7

Inside the calvarium in the epidural space.

Question 8

Branches of which artery contribute to the rete mirabile?

Answer 8

Maxillary artery

Question 9

What is the function of the rete mirabile?

Answer 9

Because it is near a venous sinus, it functions in cooling the blood entering the brain.

Question 10

One artery emerges from the rete mirabile to supply bood to the brain. Which artery is this?

Answer 10

Intracranial internal carotid artery.

Question 11

True or False: Pigs have an extracranial internal carotid artery, so do not have a rete mirabile.

Answer 11

False.

Pigs have both an extracranial internal carotid artery and a rete mirabile.

Question 12

In the horse, which two veins come together to form the external jugular vein?

Answer 12

Maxillary v.

Linguofacial v.

Question 13

What percentage of horses possess an internal jugular vein?

Answer 13

10%

Question 14

Which vein drains the abaxial muscles of the neck?

Answer 14

Deep cervical vein.

Question 15

Do small ruminents possess an internal jugular vein?

Answer 15

No.

Question 16

Which is the preferred vein for blood draws in pigs?

Answer 16

Cranial vena cava.

Question 17

Which side of the neck is preferred for blood draws in pigs? Why?

Answer 17

Right side.

Left phrenic nerve more vulnerable in location.

Thoracic duct drains on left side (possible lymph contamination).

Thyroid gland shifted to the left and caudal.

Question 18

Where does the tracheal lymph duct originate in the dog?

Answer 18

Medial retropharyngeal lymph node

Question 19

Where does the tracheal lymph duct originate in the horse?

Answer 19

Cranial deep cervical lymph node

Question 20

Where does the tracheal lymph duct originate in the cow?

Answer 20

Lateral retropharyngeal lymph node

Question 21

What are the two lymph drainage routes from the head in the pig?

Answer 21

Tracheal duct from the medial retropharyngeal lymph node.

Alternate route from the dorsal superficial cervical lymph node.

Question 22

What is the primary route of lymph drainage from the head in the pig?

Answer 22

Alternate route from the dorsal superficial cervical lymph node.

Question 23

Which two nerves must be blocked to eliminate motor and sensory innervation to the face?

Answer 23

Facial

Trigeminal

Question 24

A horse presents to you with an eyelid laceration. Which nerves to you block to repair the injury?

Answer 24

Supraorbital

Auriculopalpebral

Question 25

Which salivary gland is largest in the ruminant?

Answer 25

Mandibular

Question 26

Define “lymphocenter.”

Answer 26

A localized collection of lymphatic tissue. Can contain one or more lymph nodes.

Question 27

Identify the lymphocenters labeled 1, 2, 5, and 6.

Answer 27

1. Parotid lymphocenter (single lymph node in the bovine).
2. Mandibular lymphocenter.
3. Medial retropharyngeal lymphocenter.
4. Lateral retropharyngeal lymphocenter.

Question 28

Which lymphocenter is found immediately rostral to the parotid salivary gland?

Answer 28

Parotid lymphocenter.

Question 29

What is unique about the lymphoid tissues of equines?

Answer 29

Diffuse. Lymph nodes have a glandular appearance, and should not be mistaken for salivary glands.

Question 30

True or False: the mandibular salivary gland in the equine is located caudal to the angle of the mandible.

Answer 30

FALSE.

The equine mandibular lymph nodes are rostral to the angle of the mandible and are fused into a V shape, with the tip of the V located near the vascular notch.