Anatomy Lecture 02 (General Anatomy)

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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

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