Connective Tissue Cells and Function

• Most abundant connective tissue cell is the fibroblast.
• Collagen fibers exhibit the greatest tensile strength among connective tissue fibers.
• Glycosaminoglycans provide flexibility and support within the ground substance.
• Loose areolar connective tissue is found in the lamina propria.
• Elastin is the key protein in elastic fibers.
• Type III Collagen is the collagen fiber type present in reticular fibers.
• White adipose cells store fat as a single, large droplet.
• Brown adipose tissue functions in heat generation.
• Cartilage is a specialized connective tissue providing shock absorption.
• Reticular cells are the primary cells in reticular connective tissue.

Connective Tissue Cells & Function

• Mast cells facilitate local inflammatory responses.
• Histiocytes are resident macrophages in tissues.
• Dense irregular connective tissue resists tension in multiple directions.
• Monocytes are precursors to macrophages.
• Loose connective tissue is known as areolar connective tissue.
• Mesenchymal cells are fixed connective tissue cells found in the embryo.
• Dense regular connective tissue features parallel collagen fiber arrangement.

Connective Tissue Fibers

• Collagen fiber is the most abundant connective tissue fiber.
• Type III Collagen is the main protein in reticular fibers.
• Mucoid connective tissue is located in the umbilical cord, known as Wharton’s Jelly.
• White adipose cells have a characteristic signet ring appearance.
• Glycosaminoglycans, proteoglycans, and glycoproteins are major macromolecules in ground substance.
• Adipocytes produce leptin.
• Fibrocartilage is found in intervertebral discs.

Cartilage & Bone

• Elastic cartilage maintains shape and flexibility.
• Collagen (Type I) is the main fiber in tendons.
• Loose connective tissue is vascular connective tissue with few fibers and high ground substance.
• Areolar connective tissue is found in the submucosa of the bowel.
• Osteoclasts are bone cells responsible for bone resorption.
• Volkmann’s canals connect Haversian canals in bone.
• Chondrocytes are found in lacunae within cartilage.
• Bone is connective tissue that stores calcium and provides support.
• Osteoblasts are responsible for bone matrix synthesis.
• Reticular fibers are stained using silver stain.
• Hyaline cartilage is the cartilage type found in the trachea.
• Compact bone is bone tissue characterized by osteons.
• Osteocytes are bone cells housed in lacunae.
• Collagen type II is a major component of the interterritorial matrix.
• Brown adipocytes are multilocular fat cells.
• Canaliculi house cytoplasmic processes.

Muscle Tissue

• Skeletal muscle facilitates eye globe movement.
• Cardiac muscle contains intercalated discs.
• Smooth muscle lacks striations.
• Epimysium is the connective tissue covering the whole muscle.
• Perimysium is the connective tissue around fascicles.
• Endomysium is the connective tissue around muscle fibers.
• Sarcomeres are the functional units of muscle contraction.
• The H zone contains only thick filaments.
• The A band contains both thick and thin filaments.
• The I band contains only thin filaments.
• The Z line bisects the I band.
• Myosin is the main protein of thick filaments.
• Actin is the main protein of thin filaments.
• The sarcoplasmic reticulum is the calcium storage site in muscle.
• Smooth and cardiac muscle have a single, central nucleus.
• Skeletal muscle is under voluntary control.
• Cardiac muscle is involuntary striated muscle.
• Skeletal muscle features striated muscle with multiple peripheral nuclei.
• Smooth muscle arrangement consists of spindle-shaped cells without striations.
• Skeletal muscle arrangement consists of striated, cylindrical fibers.
• Intercalated discs are specialized junctions in cardiac muscle.
• T-tubule depolarization triggers skeletal muscle calcium release.
• Sarcomeres function in muscle contraction.
• Smooth muscle is located in the GIT, blood vessels, and uterus.
• Skeletal muscle cells are multinucleated.
• Cardiac muscle appears branched and striated under a microscope.
• Smooth muscle is the muscle type found in the urinary bladder.
• No single organ contains all three muscle types.
• Smooth muscle is responsible for peristalsis.
• The sarcomere is the smallest functional unit of muscle fiber.

Nervous Tissue

• Nervous tissue originates from the ectoderm germ layer.
• The neural tube gives rise to the CNS.
• Neural crest cells give rise to the PNS.
• Neurons are the functional units of nervous tissue.
• Neuroglial cells support neurons.
• The cerebellum is the brain division responsible for balance.
• The cerebrum is the brain division responsible for thinking.
• The brainstem is the brain division responsible for autonomic function.
• In the cerebrum, gray matter is located in the cortex.
• In the cerebrum, white matter is located in the medulla.
• The outermost layer of the cerebral cortex is the molecular layer.
• The internal pyramidal layer (V) contains the largest pyramidal cells.
• The middle layer of the cerebellum contains Purkinje cells.
• The granular layer contains small neurons in the cerebellum.
• The outer layer of cerebellar gray matter is the molecular layer.
• Cerebellar convolutions are called folia.
• Cerebral convolutions are called gyri.
• Spinal cord gray matter is H-shaped.
• The outer layer of the spinal cord is white matter.
• The inner layer of the spinal cord is gray matter.
• The posterior horns of gray matter have sensory function.
• The anterior horns of gray matter have motor function.
• Neuron cell bodies are located in gray matter.
• Myelinated fibers are located in white matter.
• The central canal is a fluid-filled space in the spinal cord.
• Nerve fibers are covered by the myelin sheath.
• The molecular layer (I) contains horizontal cells of Cajal.
• The brainstem connects the cerebrum and the spinal cord.
• The somatic nervous system is responsible for voluntary movements.
• The autonomic nervous system is responsible for involuntary functions.