Histology

1. Epithelial tissues

2. Connective tissues

3. Muscle tissues

4. Nervous tissues

Cuboidal Epithelium

• Equal in height and width

• Secretory portions of glands or in tubules of kidney and tissue covering the ovary

Squamous Epithelium

• Flat irregular outline• Scalelike• Thin• Lining blood vessels,

pericardium, pleurae, skin

Columnar Epithelium

• Packed closely together

• Protective covering for the inner surface of an organ

• Lining of the digestive tract

• Secretions

Stratified Columnar Epithelium

• This is pseudostratified

• True stratified composed of many layers

• Notice these columnar cells are ciliated

• Line trachea

Connective Tissue

• Bone• Cartilage• Dense fibrous connective

tissue• Loose fibrous connective

tissue• Liquid connective tissue

Bone

• Characterized by osteocytes in compact bone, with Haversian canals, concentric lacunae

• Found in skeleton

• Framework for movement, support, and protection

• Stores minerals; makes blood

Bone

• Dark stained areas lacunae

• Lumen are Haverian canals

Cartilage

• Chondrocytes in lacunae• Mostly intracellular• Found in pinna, ends of long bones, larynx,

nose, between vertebrae, between rib and breastbone, trachae

• Function is to cushion, lend rigidity to boneless structures, slippery surface for some joints

Types of Cartilage

Hyaline Cartilage Elastic Cartilage

Fibrous Cartilage Growth Plate

Dense Fibrous Connective Tissue

• Regularly arranged

• Collagen and fibroblasts

• Found in tendons and ligaments

• Joins muscles to bones or bone to bone; provides protection and carries blood supply

Dense Fibrous Connective Tissue

• Tendon • Irregular Dense CT

Loose Fibrous Connective Tissue

• Elastic: elastin, capsules of organs, holds organ together, lungs and vessels

• Areolar: loose weave, facial area beneath skin, collagen, support, reservoir fluids and salts

• Reticular: surrounds individual cells, acts as filler tissue and support; muscle fibers, liver, lymph nodes, and spleen

• Adipose: around organs, beneath skin, breast, cushions, insulates, and stores fat

Loose Fibrous Connective Tissue

Elastic Mucosal (Areolar)

Reticular Adipose

Liquid Connective Tissue

• Blood: found in heart and vessels; functions in respiration, nutrition, excretion, body temperature, disease protection

• Lymph: found in tissue spaces between cells, cerebrospinal fluid; functions in bathing cells, nutrition, and protection from disease

Liquid Connective Tissue

B: Red Blood Cell nucleated

A & C: Leucocytes

Lymphocytes along margin

Muscle Tissues

• Skeletal

• Smooth

• Cardiac

Skeletal Muscle

• Attached to skeleton• Voluntary control• Fibers are elongate, cylindrical, with blunt ends• Striated• Multiple Nuclei per fiber• Nuclei are peripheral• Has most rapid contraction speed• Has least duration of contraction length

Smooth Muscle

• Located in walls in stomach, arteries, and veins• Involuntary control• Fibers are elongate, spindle, with pointed ends• No striations• One nuclei per fiber• Nucleus is centrally located• Has slowest contraction speed• Has greatest duration of contraction

Cardiac Muscle

• Located in walls of heart• Involuntary control• Fibers are elongate, cylindrical, fibers branch and

fuse• Has striations• One-two nuclei per fiber• Nuclei are located centrally• Has intermediate speed of contraction• Has intermediate duration of contraction

Muscle Tissues

Skeletal Skeletal with striations

Smooth Cardiac

Nervous Tissue

• Neurons

• Glial cells

• Schwann cells

Neurons

• 3 parts: soma, dendrites, and axon• Dendrites receive inputs • Axons conducts impulses away from the

cell body toward another neuron, muscle, or gland

• 3 types of neurons: motor (muscles), sensory (sense organs), and associative (relay from sensory to motor neurons)

Glial Cells

• Many different types, including astrocytes

• Supporting cells for neurons

• Smaller and more numerous than neurons

• Give rise to most tumors in CNS

Histology

1. Epithelial tissues

2. Connective tissues

3. Muscle tissues

4. Nervous tissues

Schwann Cells

• May be categorized with glial cells

• Supporting cells found outside CNS form sheaths

• Nearly all neurons 2 micrometers or greater in diameter are myelinated-covered with Schwann cells

Nervous Tissue

Myelinated nerve cells Unmyelinated nerve cells

Astrocytes – Glial cells