University:
Glendale Community College
Course:
BIO160 | Introduction to Human Anatomy and Physiology
Academic year:

2020
Views:

286

Pages:

8
Author:

arborezmv

Sensory Receptors of the Skin Sensory Receptors of the Skin Sensory Receptors of the Skin a) Free Nerve Endings are the tips of neuron processes that are sensitive to pain (nociceptors) or change in temperature (hot and cold). Commonly found in epithelia and connective tissue. b) Merkel’s (tactile) Endings are free nerve endings associated with a Merkel’s cell. This is a sensitive mechanoreceptor for sensing textures, edges and shapes. Encapsulated Nerve Endings: c) Pacinian (Lamellated) Corpuscles sense deep pressure, stretch, and vibration. Nerve ending is wrapped in a capsule of many layers of Schwann cells. Found in dermis of hands, feet, breasts and genitals. d) Krause’s End Bulbs are similar to Merkel’s disks, but are found in mucus membranes of the mouth and are cold temperature receptors. e) Meissner’s Corpuscles sense light touch and texture. Located in dermal papillae and are abundant in the lips. f) Ruffini’s Corpuscles are sensitive to stretch or compression of skin. Sensory Receptors of the Skin The Dermis • Dermal Papillae (also called dermal ridges) form the Papillary Layer of the Dermis and is composed of loose connective tissue • Collagen Fibers of the Reticular Layer of the Dermis form a dense irregular connective tissue The Dermis • Thickness = 0.6mm to 3mm • Composition – fibroblasts, collagen fibers, elastic fibers, reticular fibers, blood vessels, nerves, hair follicles and glands • Layers – the dermal papillae of the papillary layer are composed of areolar connective tissue. – reticular layer is the deeper part of dermis and is composed of dense irregular connective tissue. • Dermal papillae are upward extensions of the dermis that interdigitate with the epidermis and correspond to the ridges of the fingerprints. Blood Vessels of the Dermis and Hypodermis The Hypodermis • The hypodermis is also called the subcutaneous tissue or the superficial fascia. • The adipose of the hypodermis is called the subcutaneous fat. • Hypodermis functions to store energy (in fat) and to thermally insulate • Hypodermic injections deliver substances into the highly vascular tissue of the hypodermis.