ansc 2202 full exam

Neuron

Cells that are the functional units of the nervous system; receive, transmit, and store information.

Cell body

Control center of the neuron; does not regenerate.

Axon

Long process of the neuron that carries information to other neurons or tissue; can regenerate.

Dendrites

Short, branched processes of a neuron; receive information and send it to the cell body.

Myelin sheath

Covers the axon; speeds up the impulse and is made of Schwann cells.

Synapse

Synaptic knob; end of the neuron that contacts other neurons or tissues; releases neurotransmitters.

Nervous system

Highly organized control center allowing the body to react appropriately to changes in its internal and external environment.

Nerve

A whitish fiber or bundle of fibers that transmits impulses of sensation to the brain or spinal cord, and impulses from these to the muscles and organs.

Central nervous system

Brain and spinal cord.

Peripheral nervous system

All other nerves to the peripheral tissues (cranial, spinal, and sciatic nerves).

Sensory neurons

Afferent neurons; impulses from periphery to CNS, detect pain, touch, itch, temperature, and stretching of muscles.

Motor neurons

Efferent neurons; impulses from CNS to periphery (muscles, glands).

Interneuron

Short neurons that enable communication between sensory neurons, CNS, and motor neurons (function in reflexes, learning, making decisions).

Brain

Complex organ that is the center of the CNS; made up of the cerebrum, brain stem, and cerebellum.

Cerebrum

Main part of the brain responsible for memory, senses, and learning.

Frontal lobe

Part of the brain responsible for motor functions.

Occipital lobe

Part of the brain responsible for vision functions.

Temporal lobe

Part of the brain responsible for hearing centers.

Parietal lobe

Part of the brain responsible for temperature, pressure, touch, and pain sensations.

Thalamus

Round mass in the brain stem; relays sensation, spatial sense, and motor signals to the cerebrum; regulates consciousness, sleep, and alertness.

Pineal gland

Secretes melatonin (circadian and seasonal rhythms) and is small in dogs but prominent in larger species.

Ventricles in the brain

Filled with cerebrospinal fluid, provides nutrients, and removes waste.

Hypothalamus

Produces hormones (gonadotropin-releasing hormone); includes optic chiasm and pituitary gland.

Optic chiasm

Where optic nerve (CN II) crosses.

Pituitary gland

Stores and produces hormones for growth, maturation, and reproduction.

Pons

Part of the brain stem; relays messages between cerebrum and cerebellum, involved in sleep and dreaming.

Medulla oblongata

Part of the brain stem; controls heart rate, blood pressure, respiratory rate, coughing, sneezing, vomiting, and swallowing.

Cerebellum

Also known as arbor vitae (tree of life); controls balance and coordination.

Cranial nerves

12 pairs going to/from the brain stem; names mostly indicate functions.

CN I: Olfactory

Responsible for the sense of smell.

CN II: Optic

Responsible for vision.

CN III: Oculomotor

Controls eye movements and pupil size.

CN IV: Trochlear

Controls one muscle of the eyeball.

CN V: Trigeminal

Sensory and motor functions related to the forehead, lateral eye, nasal cavity, and chewing.

CN VI: Abducent

Motor function for the eyeball.

CN VII: Facial

Motor function for facial expressions and sensory to the rostral 2/3 of the tongue.

CN VIII: Vestibulocochlear

Responsible for sound and equilibrium.

CN IX: Glossopharyngeal

Controls tongue, pharynx, and swallowing.

CN X: Vagus

Controls the palate, pharynx, larynx, trachea, esophagus, and thoracic/abdominal organs.

CN XI: Accessory

Controls larynx, esophagus, swallowing, and vocalization.

CN XII: Hypoglossal

Controls muscles of the tongue.

Meninges

Three layers covering the brain and spinal cord: dura mater, arachnoid, and pia mater.

Dura mater

Thickest, most external layer of meninges; fused with the periosteum of the skull.

Arachnoid

Delicate layer of meninges attached to dura mater.

Pia mater

Innermost layer of meninges, adheres to the brain/spinal cord; subarachnoid space contains cerebrospinal fluid.

Limbus

Edge or border of an anatomical structure.

Sclera

The white outer layer of the eyeball.

Cornea

Transparent front part of the eye covering the iris and pupil.

Lens

Transparent structure in the eye that helps to focus light on the retina.

Tapetum lucidum

Reflective layer behind the retina in some animals that enhances night vision.

Iris

Colored part of the eye that regulates the size of the pupil.

Pupil

Opening in the center of the iris that allows light to enter the eye.

Retina

Layer at the back of the eye that contains photoreceptor cells.

Optic disc

Point where the optic nerve exits the eye.

Optic nerve

Nerve that transmits visual information from the retina to the brain.

Anterior chamber

Chamber between the cornea and the iris.

Posterior chamber

Chamber between the iris and the rest of the eye.

Vitreous chamber

Large space in the eye filled with vitreous humor.

Vitreous humor

Jelly-like substance behind the lens of the eye that maintains its shape.

Lateral and medial canthus

Where the eyelids meet at the corners of the eyes.

Cilia

Eyelashes.

Conjunctiva

Pink mucous membrane lining the eyelids.

Appendicular skeleton

Refers to the limbs (appendages).

Antebrachium

Forearm consisting of the radius and ulna.

Manus

Distal portion (hand) including carpus, metacarpus, and digits.

Equine metacarpus

Metacarpal bones II-IV; MC I is missing, with MC II and IV as splint bones.

Splints

Inflammation of the horse's interosseous ligament between the splint bones and cannon bone.

Periosteitis

Inflammation of the periosteum; common in young, large breed dogs.

Ruminant metacarpus

MC III and IV are fused; MC II is missing, MC I is small.

Carnivores metacarpus

MC I is the dewclaw; MC II-V are present.

Digits

Correspond to fingers and toes; vary in number by species.

Proximal phalanx

Long pastern bone (P1).

Middle phalanx

Short pastern bone (P2).

Distal phalanx

Coffin bone (P3).

Ruminant digits

Weight-bearing toe bones (3rd and 4th); non-weight bearing digits (2nd and 5th).

Sesamoid bones in ruminants

Two proximal and one distal sesamoid bones per foot.

Carnivore digits

Four weight bearing digits (II-V) and one non-weight bearing dewclaw (I).

Ungual process

Curved, cone-like extension of the distal phalanx covered by the horny claw.

Horny claw

Curved, fingernail-like projection covering and protecting the ungual process.

Carnivore sesamoid bones

Two sesamoid bones on the palmar/plantar side.

Pes

Hindpaw or distal portion of the pelvic limb; includes tarsus, metatarsus, and digits.

Proximal portion of the pelvic limb

Includes os coxae, femur, patella, tibia, and fibula.

Metatarsal III

Cannon bone.

Metatarsal II and IV

Splint bones.

Metatarsals in ruminants

Fused MC III and IV; MT I is missing.

Metatarsals in carnivores

MT I is small dewclaw; MT II-V are present.

Arthrology

Study of joints.

Articulation

Joining of two or more bones to create a joint.

Simple joints

Two bones that articulate with each other.

Compound joints

More than two bones articulating with one another.

Fibrous joint

Temporary joint with little or no movement, often found in young animals.

Cartilaginous joint

United by fibrocartilage or hyaline cartilage; allows limited movement.

Synovial joint

True joint encapsulated by a membrane and filled with synovial fluid.

Scapulohumeral joint

Joint between scapula and humerus.

Cubital joint

Joint between humerus, radius, and ulna.

Carpus joint

Joint between radius/ulna and metacarpals.

Metacarpophalangeal joint

Joint between metacarpal, proximal phalanx, and proximal sesamoid bones.

Proximal interphalangeal joint

Joint between proximal and middle phalanx.

Distal interphalangeal joint

Joint between middle and distal phalanx.

Ringbone

Periosteal bone deposition in the distal limb.