Integumentary System

The Integumentary System

• The integumentary system is the set of organs forming the outermost layer of an animal's body, comprising the skin and its appendages, which act as a physical barrier between the external environment and the internal environment.
• It protects the body from pathogens and chemicals, maintains water balance, regulates body temperature, and detects sensations like pain, pressure, and temperature.

Parts of the Skin

• The skin is composed of three basic layers: epidermis, dermis, and subcutaneous tissue.
• The epidermis is the outermost layer, composed of keratinized, stratified squamous epithelium, with four or five layers of epithelial cells.
• The dermis is the layer below the epidermis, made of two layers of connective tissue, containing blood and lymph vessels, nerves, and other structures like hair follicles and sweat glands.
• The subcutaneous tissue (hypodermis) is the layer below the dermis, connecting the skin to underlying fascia of bones and muscles, and consisting of well-vascularized, loose, areolar connective tissue and adipose tissue.

Epidermis

• The epidermis has four types of cells: keratinocytes, melanocytes, Merkel cells, and Langerhans cells.
• Keratinocytes produce keratin, a fibrous protein that aids in skin protection, and form the epidermal water barrier by making and secreting lipids.
• Melanocytes produce melanin, a pigment found in the skin, eyes, hair, nasal cavity, and inner ear.
• Merkel cells are oval-shaped mechanoreceptors essential for light touch sensation, found in the skin of vertebrates.
• Langerhans cells are immune cells found primarily in the epidermis, stimulating and suppressing the adaptive immune response.

Functions of the Skin

• Covers and protects internal organs from injury, bacteria, and environmental changes
• Regulates body temperature through sweat glands and blood vessels
• Aids in awareness of the environment through sensory receptors
• Protects the body against fluid loss through the epidermal water barrier
• Eliminates waste products through perspiration
• Produces vitamin D when exposed to UV radiation
• Plays a role in nonverbal communication through facial expressions and skin sensations

Disorders of the Integumentary System

• Acne: a skin disturbance that typically occurs on areas rich in sebaceous glands, caused by hormonal changes and overproduction of sebum.
• Psoriasis: a chronic autoimmune condition causing red, scaly patches on the skin.
• Burns: damage to the skin caused by intense heat, radiation, electricity, or chemicals, leading to a massive loss of fluid and increased susceptibility to infection.
• Eczema: an allergic reaction causing dry, itchy patches of skin resembling rashes.
• Carcinoma: a type of skin cancer caused by abnormal cell division, often due to overexposure to UV radiation.
• Keloid: a raised or hypertrophic scar caused by an overproduction of scar tissue during the healing process.
• Injuries: wounds, scars, and calluses caused by sharp objects, heat, or excessive pressure or friction to the skin.

The Integumentary System

• The integumentary system is the set of organs forming the outermost layer of an animal's body, comprising the skin and its appendages, which act as a physical barrier between the external environment and the internal environment.
• It protects the body from pathogens and chemicals, maintains water balance, regulates body temperature, and detects sensations like pain, pressure, and temperature.

Parts of the Skin

• The skin is composed of three basic layers: epidermis, dermis, and subcutaneous tissue.
• The epidermis is the outermost layer, composed of keratinized, stratified squamous epithelium, with four or five layers of epithelial cells.
• The dermis is the layer below the epidermis, made of two layers of connective tissue, containing blood and lymph vessels, nerves, and other structures like hair follicles and sweat glands.
• The subcutaneous tissue (hypodermis) is the layer below the dermis, connecting the skin to underlying fascia of bones and muscles, and consisting of well-vascularized, loose, areolar connective tissue and adipose tissue.

Epidermis

• The epidermis has four types of cells: keratinocytes, melanocytes, Merkel cells, and Langerhans cells.
• Keratinocytes produce keratin, a fibrous protein that aids in skin protection, and form the epidermal water barrier by making and secreting lipids.
• Melanocytes produce melanin, a pigment found in the skin, eyes, hair, nasal cavity, and inner ear.
• Merkel cells are oval-shaped mechanoreceptors essential for light touch sensation, found in the skin of vertebrates.
• Langerhans cells are immune cells found primarily in the epidermis, stimulating and suppressing the adaptive immune response.

Functions of the Skin

• Covers and protects internal organs from injury, bacteria, and environmental changes
• Regulates body temperature through sweat glands and blood vessels
• Aids in awareness of the environment through sensory receptors
• Protects the body against fluid loss through the epidermal water barrier
• Eliminates waste products through perspiration
• Produces vitamin D when exposed to UV radiation
• Plays a role in nonverbal communication through facial expressions and skin sensations

Disorders of the Integumentary System

• Acne: a skin disturbance that typically occurs on areas rich in sebaceous glands, caused by hormonal changes and overproduction of sebum.
• Psoriasis: a chronic autoimmune condition causing red, scaly patches on the skin.
• Burns: damage to the skin caused by intense heat, radiation, electricity, or chemicals, leading to a massive loss of fluid and increased susceptibility to infection.
• Eczema: an allergic reaction causing dry, itchy patches of skin resembling rashes.
• Carcinoma: a type of skin cancer caused by abnormal cell division, often due to overexposure to UV radiation.
• Keloid: a raised or hypertrophic scar caused by an overproduction of scar tissue during the healing process.
• Injuries: wounds, scars, and calluses caused by sharp objects, heat, or excessive pressure or friction to the skin.

Learn about the outermost layer of an animal's body, including the skin and its appendages, and how it protects the internal environment from external pathogens and chemicals.