B. Synovial Membranes Synovial membranes are composed solely of connective tissue, and line freely moveable joint capsules that do not open to the exterior. These membranes are composed of a layer of adipose and areolar CT, along with specialized cells called synoviocytes . Synoviocytes secrete s ynovial fluid that lubricates and nourishes cartilage within the joints.
D. Muscle Tissue
Muscle tissue is responsible for the production of movement, the maintenance of body postures, and the production of heat. The cells that make up muscle tissue are elongated fibres that can generate force using ATP.
Types of Muscle Tissue
i. Skeletal Muscle
Usually attached to the bones of the skeleton with s triations visible under microscope. This muscle tissue is considered v oluntary because it can contract or relax by conscious control.
ii. Cardiac Muscle
This tissue forms most of the wall of the heart. It is striated like skeletal muscle however, it is involuntary . Cardiac muscle is branched and attached end to end by transverse thickenings of plasma membrane called Intercalated Discs containing both desmosomes and gap junctions. Intercalated discs are unique only to cardiac muscle.
iii. Smooth Muscle
Located in the walls of hollow internal structures such as blood vessels, and airways. Contraction is involuntary and helps to constrict the lumen of blood vessels, breakdown food moving along the digestive tract, move fluids through the body and eliminate wastes. This muscle tissue lacks striations and therefore is termed “smooth”. Many gap junctions connect individual fibres in some smooth muscle tissues.
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