Integument and Mammals Overview

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Questions and Answers

What is the primary function of eccrine glands?

To waterproof and lubricate hair and skin

To secrete a viscous fluid involved in scent production

To secrete a watery fluid primarily for evaporative cooling (correct)

To provide chemical communication between mammals

Which of the following correctly describes a function of the apocrine glands?

They secrete an oily substance that waterproofs skin.

They begin to function at sexual maturity and are associated with hair follicles. (correct)

They primarily assist in thermoregulation through evaporative cooling.

They are found in hairless regions and function before puberty.

How do spines of animals like porcupines serve as a defense mechanism?

They produce heat to keep the animal warm during threats.

They cause physical injury to potential predators. (correct)

They camouflage the animal from predators.

They emit a foul odor to deter attackers.

What role do raised hairs play in communication among some mammals?

They can convey warnings of anger or fear. Signup and view all the answers

What is one significant characteristic of nocturnal and burrowing mammals regarding their tactile information?

Their sensory hairs are often particularly long. Signup and view all the answers

What condition is associated with overactive sebaceous glands?

Acne Signup and view all the answers

What is the significance of molting in animals like snowshoe hares and arctic foxes?

It allows them to adapt their camouflage according to season. Signup and view all the answers

Which gland is responsible for producing sebum, which waterproofs and lubricates hair and skin?

Sebaceous glands Signup and view all the answers

Which of the following statements regarding scent glands is true?

Scent glands can have varied locations across different species. Signup and view all the answers

What significant characteristic differentiates antlers from true horns?

Antlers are shed annually, whereas true horns are permanent. Signup and view all the answers

Which structure primarily produces and secretes milk in mammary glands?

Alveoli Signup and view all the answers

In which manner do mammary glands usually deliver milk to the young?

Via ducts or directly to the surface. Signup and view all the answers

What role do true horns play in the animal kingdom?

Serve as a permanent structure for combat and protection. Signup and view all the answers

Which subclass of mammals is classified under Monotremata?

Echidna Signup and view all the answers

What is the primary role of keratinocytes in the epidermis?

To produce keratin Signup and view all the answers

Which layer of the epidermis contains dead cells filled with keratin?

Stratum Corneum Signup and view all the answers

Which of the following correctly describes the general function of sebaceous glands in mammals?

To keep skin moist and reduce water loss Signup and view all the answers

What type of mammals are classified as Eutheria?

Viviparous mammals with a placenta Signup and view all the answers

What structure in the skin is responsible for generating hair?

Hair follicle Signup and view all the answers

Which term refers to the muscle that raises hair follicles and creates goosebumps?

Arrector pili muscle Signup and view all the answers

Which order of mammals includes both primates and carnivores?

Theria Signup and view all the answers

Study Notes

Subphylum Vertebrata - Mammalia

Mammals are a subgroup of vertebrates.
They are introduced in the study.
Their integument (skin) is discussed in multiple categories.

Integument - General

The epidermis is the outer layer of skin.
It is a stratified epithelium made up of multiple layers of cells.
Keratinocytes, present in the epidermis, produce keratin.
Stratum corneum is the outermost layer of dead keratinized cells.
Stratum basale, underneath the stratum corneum, contains undifferentiated cells that generate newer epidermal layers.
Specialized modifications of the epidermis, such as glands and hair follicles, reside in the dermis.
Sebaceous glands, sweat glands, hair follicles and nerve endings are present in the dermis

Integument - Hair

Hair has various functions.
Insulation is one of its most important functions.
Hair can indicate or communicate warnings of aggression or fear.
This is because raised hair is a sign of anger or fear, controlled by the arrector pili muscle.
It provides tactile information from the environment.
Nocturnal and burrowing mammals are known to have long hair that aids in sensing the surrounding area.
It plays a protective role. (e.g. spines of porcupines).
Hair can also provide camouflage.
Seasonal changes may result in hair changes in animals (e.g., snowshoe hare, arctic foxes).

Integument - Glands

Mammals have a wide range of glands in their integument.
All glands are derivatives of the epidermis.
They are categorized in four main groups.

1. Sweat Glands

(i) Eccrine glands: Not connected to hair follicles, active before puberty.
They secrete a watery fluid, primarily a sodium chloride solution, and play a pivotal role in evaporative cooling.
They are found in hairless regions like foot pads.
(ii) Apocrine glands: Connected to hair follicles, become functional in maturity.
Secretions are viscous fluids and are involved in chemical communication.
They are found around genitals, armpits.
Secretions can create odors when interacting with bacteria.

2. Sebaceous Glands

These glands are found all over the body in association with the hair follicles, including copious quantities in the scalp and face.
They produce an oily secretion called sebum that lubricates and waterproofs hair and skin.
Overactive glands can result in acne.

3. Scent Glands

Modified sebaceous or apocrine glands.
Secrete pheromones used to communicate or mark territory, warn or intimidate.
Locations differ greatly depending on the species (e.g., deer, skunks, wolves).

4. Mammary Glands

Present in all female mammals, and in males in a rudimentary form.
These glands produce and release milk for nursing offspring in the process of lactation.
Composed of alveoli (clusters of milk producing glands), which open into ducts.

Integument - Specializations

True Horns: Keratinized coverings around bone cores, not branched, found in both sexes.
Antlers: Bone cores covered in vascularized skin (velvet), branched, typically found in males, shed annually. They are used for social display, fighting, and recognition.

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Description

This quiz covers the integumentary system of mammals, focusing on the structure and function of the skin, including the epidermis and dermal components. Additionally, it explores the significance of hair in mammals, emphasizing its role in insulation and communication. Test your understanding of how these features contribute to the biology of vertebrates.