Anat 121 | Gross Anatomy Lecture 3

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Questions and Answers

What is the primary function of a dog's vibrissae?

To perceive air currents and temperature (correct)

To enhance the dog's hearing abilities

To provide insulation to the dog's body

To help with the dog's balance

Which type of coat classification includes breeds like Cocker Spaniel and Poodle?

Short Hair

Other classification

Long Hair (correct)

Normal Coat

What type of muscle is responsible for the erection of hairs in response to cold, fear, or anger in animals?

Skeletal Muscle

Visceral Muscle

Cutaneous Trunci Muscle

Erector Pili Muscle (correct)

Which of the following statements about Guard hairs is correct?

They act as a topcoat and prevent skin injuries. Signup and view all the answers

Which type of sweat gland in dogs secretes sweat directly onto the skin surface?

Eccrine sweat glands Signup and view all the answers

What role do the glands in canine skin serve?

They play a role in thermoregulation and hydration. Signup and view all the answers

What is the purpose of the Cutaneous Trunci muscle?

To twitch the skin Signup and view all the answers

What type of hair classification would a Boxer belong to?

Short Hair Signup and view all the answers

Where are apocrine sweat glands primarily located?

In the armpits and genital area Signup and view all the answers

What is the primary function of sebaceous glands?

Oil secretion Signup and view all the answers

What do vibrissae primarily help a dog to do?

Measure distance and detect air currents Signup and view all the answers

Which glands secrete cerumen?

Glands of the ear canal Signup and view all the answers

What role do the Bartholin glands play in the female reproductive system?

Secreting mucus during estrus Signup and view all the answers

Where are the glands of the anal sac located?

In the 4 and 8 o'clock position of the anal canal Signup and view all the answers

What is the primary purpose of the supracaudal gland?

Mark territory and contribute to scent Signup and view all the answers

What is the main function of claws in animals?

To provide traction, defense, and catch prey Signup and view all the answers

What is the primary function of the dermis?

Housing of vessels and nerve endings Signup and view all the answers

Which layer of the epidermis is known as the 'horny layer'?

Stratum corneum Signup and view all the answers

Which skin pigment is primarily responsible for the brown color in skin?

Melanin Signup and view all the answers

What type of connective tissue makes up the hypodermis?

Adipose and areolar tissue Signup and view all the answers

Which layer of the skin is continuous with mucous membranes?

Epidermis Signup and view all the answers

Which layer of the epidermis contains granules and is referred to as the granular layer?

Stratum granulosum Signup and view all the answers

Which structure in the skin is primarily responsible for warmth?

Hair Signup and view all the answers

What type of cells are primarily involved in the skin's immune response?

Macrophages Signup and view all the answers

What is the thickest area of skin typically found in dogs?

Neck region Signup and view all the answers

Which part of the hair is embedded in the skin?

Root Signup and view all the answers

Study Notes

Integumentary System Overview

Strong and flexible connective tissue provides a protective covering for the body, known as "hide."
Composed of diverse cells including fibroblasts, macrophages, mast cells, and white blood cells (WBCs).
Contains collagen, elastic, and reticular fibers, ensuring durability and elasticity.

Skin (Cutis)

One of the largest organs, comprising about 16% of body weight.
Continuous with mucous membranes of the respiratory, digestive, and urogenital tracts.
Thickness varies: thickest in the neck region, thinner over the sternum, and thinnest on the ventral abdomen.

Skin Functions

Protects against microorganisms and chemicals.
Acts as a sensory organ and site for Vitamin D synthesis.
Regulates temperature and prevents dehydration.

Layers of the Skin

Comprised of three main layers: Epidermis, Dermis, and Hypodermis.

Epidermis

Most superficial layer, composed of non-vascular stratified squamous epithelium.
Contains five layers including:
- Stratum Basale
- Stratum Spinosum
- Stratum Granulosum
- Stratum Lucidum (absent in nasal skin)
- Stratum Corneum

Dermis

Rich in vessels, nerves, and glands, providing strength and flexibility.

Hypodermis

Contains fatty tissue, anchoring the skin while storing fat.
Known as "subcutaneous tissue," plays a role in insulation.

Skin Coloration

Determined by three pigments:
- Melanin: primary determinant.
- Carotene: from orange and yellow vegetables.
- Hemoglobin: gives a pink hue to lighter skin.

Skin Appendages

Includes hair, hair follicles, sebaceous (oil) glands, and sudoriferous (sweat) glands.

Hair Structure and Function

Comprises three concentric layers: Medulla, Cortex, and Cuticle, made of hard keratin.
Functions include warmth, touch sensitivity, and protection.

Hair Classifications in Dogs

Normal Coat: e.g., German Shepherd, Wolf.
Short Hair: e.g., Boxer.
Long Hair: e.g., Cocker Spaniel, Poodle.
Diverse types based on characteristics like straight, bristle, or wavy.

Erector Pili Muscle

Responsible for hair erection in response to cold or fear, known as piloerection.

Glands of Canine Skin

Sweat Glands:
- Eccrine: Secretes sweat directly onto skin surface.
- Apocrine: Secretes fluid into hair follicles, found in regions like armpits.
Sebaceous Glands:
- Secretes oil that moisturizes and protects skin.

Vibrissae (Whiskers)

Enlarged tactile hairs that aid in measuring distance in dim light and sensing air currents.

Bartholin Glands: Secrete mucus; most active during estrus.
Glands of Anal Sac: Contribute to foul-smelling viscous liquids.
Supracaudal Gland: Involved in scent marking and communication.

Claws and Digital Pads

Claws provide traction, defense, and help in catching prey.
Digital pads assist in locomotion and grip, essential for movement.

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Description

This quiz covers the third lecture of Anat 121 focusing on the integumentary system. It discusses the structure and function of the dermis, including the absence of certain skin layers like stratum granulosum and stratum lucidum. Explore the characteristics and cellular composition of the skin.