Anatomy Lecture 02 (General Anatomy)

Anatomy Lecture 02 (General Anatomy) Blood vessel,Lymphatic system,Membranes of body,Cartilage,Joints

INTRODUCTION

• Blood vessel
• Lymphatic system
• Membranes of body
• Cartilage
• Joints

BLOOD VESSELS

Blood vessels are of three types

• Arteries
• Veins
• capillaries

ARTERIES

• Arteries transport oxygenated blood from heart and distribute it to various tissues of body by means of their branches
• Arteries do not have valves

ARTERIES

• The joining of branches of arteries is called as an anastomosis
• The wall of an artery is composed of 3 layers
• Tunica intima (inner)
• Tunica media (middle)
• Tunica adventitious (outer)

ARTERIOLES

• The smallest artery is 0.1mm in diameter and is referred as arteriole
• Vessel just proximal to the capillary
• Size varies from 100µm to 12µm

TYPES OF ARTERIES- DEPENDING UPON THE STRUCTURE OF TUNICA MEDIA

Elastic arteries/ large arteries

• Tunica media is composed of elastin

Muscular arteries/ medium arteries/small arteries

• Tunica media is composed of smooth muscle cells

TYPE OF ARTERIOLES – DEPENDING UPON FUNCTION

AFFERENT ARTERIOLES

• Convey blood towards a center
• E.g., afferent arterioles conveying blood towards Bowman’s capsule in kidney (opposite to efferent)

EFFERENT  ARTERIOLES

• Convey blood away from a center
• E.g., efferent arterioles conveying blood away from Bowman’s capsule in kidney

VEINS

• Vessels that transport blood back to the heart
• Carry deoxygenated blood from tissues towards heart
• Many have valves
• The smallest vein are called venules
• Medium sized deep arteries are accompanied by two veins called venae comitants

CAPILLARIES

• Microscopic vessels in the form of a network connecting arterioles to venules
• Pertaining to or resembling a hair
• In tips of  fingers and toes, direct connections occur between arteries and veins without intervention of capillaries
• Site of such connections are referred as arteriovenous anastomosis

TYPES OF CAPILLARIES

• Continuous capillaries

No pores are seen in them- skin, connective tissue, skeletal muscle, lungs, brain

• Fenestrated capillaries

capillaries having endothelial cells linning which show characteristic pore system – renal glomeruli, intestinal villi, endocrine glands, pancreas

• Sinusoids or sinusoidal capillaries

Dilated capillaries lined by reticuloendothelial cells- liver, spleen, parathyroid gland etc

LYMPHATIC SYSTEM

• The lymphatic system is part of a circulatory system, comprising a network of lymphatic vessels that carry a clear fluid called lymph directionally towards the heart
• Lymphatic system is essentially a drainage system and there is no circulation
• Lymph is the name given to tissue fluid once it had entered the lymphatic vessel

COMPOSITION OF LYMPHATIC SYSTEM

• Lymph vessels
• Lymph nodes
• Lymph

LYMPHATIC SYSTEM

• The tonsils, adenoids, spleen and thymus are all part of the lymphatic system
• There are 600 to 700 lymph nodes in the human body
• Nodes filter the lymph before it returns to the circulatory system

LYMPHATIC TISSUE

• Lymphatic tissues are a type of connective tissue that contains large numbers of lymphocytes
• Lymphatic tissue is essential for the immunologic defences of body against bacteria and viruses
• Lymphatic tissue is organized into organs: thymus, lymph nodes, spleen, and lymphatic nodules

LYMPHATIC VESSELS

• Are tubes that assist cardiovascular system in removal of tissue fluid from tissue spaces of body
• Vessels then return fluid to the blood
• They are found in all tissues and organs of body except central nervous system, eyeball, internal ear, epidermis of skin, cartilage and bone

LYMPH CAPILLARIES

• Network of fine vessels that drain lymph from the tissue
• The capillaries are in turn drained by small lymph vessels, which unite to form large lymph vessels
• Before lymph is returned to the blood stream it passes through lymph nodes
• The vessels that carry lymph to lymph node are afferent lymph vessels and that carry away from node are efferent lymph vessels

LYMPH NODES

• Kidney shaped structures
• Vary in size
• Pink in alive persons
• Hilar lymph nodes – black
• Pre-aortic – white in colour
• Dead bodies – brownish

MEMBRANES OF BODY

• Membranes are flat sheets of tissue
• Cover or line parts of the body
• Typically composed of epithelial cells and connective tissue

TYPES OF MEMBRANES

• Mucous membrane
• Serous membrane
• Cutaneous membrane
• Synovial membrane
• Meninges

MUCOUS MEMBRANE

• Also called mucosa
• Line inside of cavities that open directly to exterior environment
• It line gastrointestinal tract, respiratory tract, reproductive tracts and urinary tract
• This type of membrane is composed of an epithelial cell layer and an underlying connective tissue layer

SEROUS MEMBRANE

• Also called serosa
• Line cavities of body that do not open directly to external environment
• Lines chest and abdominal cavities, covers liver, spleen, kidneys, heart etc.
• Made of two layers: a layer to line a cavity, called the parietal membrane, and a layer to cover an organ, called the visceral layer

The cutaneous membrane, also known as skin, covers entire body

• The synovial membrane secretes synovial fluid to lubricate joint space, making motion much easier

MENINGES

• Covering brain is a dense connective tissue membrane, composed of three layers – meninges
• The outer most layer – Dura mater
• The second layer – Arachnoid mater
• The inner most layer – Pia mater

CARTILAGE

• Cartilage is a form of connective tissue in which cells and fibers are embedded in a gel like matrix

TYPES OF CARTILAGE

• Hyaline cartilage
• Fibrocartilage
• Elastic cartilage

HYALINE CARTILAGE

• It has a great resistance to resistance
• Covers the articular surfaces of nearly all synovial joints
• It is incapable of repair when fractured

FIBROCARTILAGE

• Has many collagen fibers embedded in a small amount of matrix
• It is found in discs within the joints e.g. TMJ
• If damaged, it repairs slowly

ELASTIC CARTILAGE

• Posses large numbers of elastic fibers embedded in matrix
• It is flexible
• Found in auricle of ear, epiglottis
• If damaged, repair itself.

JOINTS

• A site where two or more bones come together, whether or not movement occurs between them, is called a joint.
• Joints are classified according to the tissue that lie between the bones.

TYPES OF JOINTS

• Fibrous joint
• Cartilaginous joint
• Synovial joint

SYNOVIAL JOINT

• The articular surfaces of the bones are covered by a thin layer of hyaline cartilage separated by a joint cavity
• The cavity of joint is lined by synovial membrane which extends from margins of one articular surface to other
• The articular surface is protected on outside by a capsule of the joint
• The articular surfaces of synovial joint are lubricated by a viscous fluid called synovial fluid

TYPES OF SYNOVIAL JOINT

• Plane joint
• Hinge joint
• Pivot joint
• Condyloid joint