Internal Surfaces Of The Body Flashcards
(23 cards)
What does a mucous membrane line?
- Internal surfaces which open to the EXTERIOR
- Alimentary tract
- Respiratory tract
- Urinary tract
What surfaces consist of serous membranes?
- Internal surfaces which do not open to the exterior
- Pericardium
- Pleural sac
- Peritoneum
What is the role of serous membranes?
Secrete watery lubricant to allow friction free movement of the structures they surround
What does a serous membrane consist of?
- Simple squamous epithelia (MESOTHELIUM)
- CONNECTIVE TISSUE which attaches the mesothelium to the surrounding tissues and carries blood vessels and nerves
What does a mucous membrane consist of?
- Epithelia (type depends on site; MUCOUS SECRETING)
- Lamina propria (connective tissue which contains Peyer’s patches, neutrophils etc.)
- Muscularis mucosae (smooth muscle layer in alimentary tract only)
Describe the layers of the gut wall
- Innermost MUCOSA (epithelia, lamina propria and muscularis mucosae)
- SUBMUCOSA (contains glands, blood vessels and nerves)
- MUSCULARIS EXTERNA (2 layers of smooth muscle - inner circular and outer longitudinal)
- Outermost SEROSA (thin layer of mesothelium, visceral peritoneum in which the peritoneal organs invaginate)
Describe the composition of the oesophageal wall
- Innermost EPITHELIA (stratified squamous non-keratinised)
- LAMINA PROPRIA (loose connective tissue bearing vessels and cells of immune system)
- MUSCULARIS MUCOSA (thin layer of smooth muscle cells)
- SUBMUCOSA (subtending layer of connective tissue bearing mucus secreting glands)
- MUSCULARIS EXTERNA (2 layers of smooth muscle which move food by peristalsis - inner circular, outer longitudinal)
- Outermost ADVENTITIA (thin outermost layer of loose connective tissue)
What does the submucosa consist of?
- Blood vessels
- Lymph vessels
- Nerves
- Mucous secreting glands
What does the lamina propria consist of?
- Blood vessels
- Peyer’s patches
- Neutrophils
- Macrophages
- Collagen
What are rugae and where are they found?
- Found in the membrane of the stomach
- Folds in the gastric mucosa forming longitudinal ridges in the empty stomach
Describe the composition of the stomach lining
- EPITHELIA (simple columnar for absorption)
- GASTRIC MUCOSA (secretes acid, digestive enzymes and gastrin)
- MUSCULARIS MUCOSA (thin layer of smooth muscle cells)
- SUBMUCOSA
- MUSCULARIS EXTERNA (3 layers of smooth muscle - circular, oblique and longitudinal)
- RUGAE (folds in the gastric mucosa forming longitudinal ridges)
What type of epithelia are present in the jejunum?
Simple columnar
What 4 components make up the respiratory tract?
- Trachea
- Bronchi
- Bronchioles
- Alveoli
What type of epithelia are found in the trachea?
Pseudostratified ciliated epithelia
What is the role of hyaline cartilage in the respiratory tract?
Prevents collapsing of airways
Describe the composition of the trachea wall
- Pseudostratified ciliated epithelia
- Submucosa
- Fibroelastic membrane
- Hyaline cartilage (C shaped)
- Adventitia
Explain how the walls of the bronchus differ to that of the walls of the bronchioles
- Bronchus contains pseudostratified ciliated epithelia whereas the bronchioles have non/ciliated simple cuboidal
- Bronchus has C shaped hyaline cartilage but bronchioles do not
- Bronchioles do not have a submucosa
- Both have smooth muscle layer surrounding epithelia
Describe the arrangement of cells in the alveoli of the lungs
- PURELY EPITHELIAL
- 90% Type I cells are SIMPLE SQUAMOUS and allow gaseous exchange with surrounding capillaries
- 10% Type II cells are SIMPLE CUBOIDAL and secrete surfactant to prevent collapsing of air sacs
- NUMEROUS MACROPHAGES line the alveolar surface
What are the advantages of transitional epithelia in the wall of the bladder?
- Allow distending of bladder
- Tight junctions make it impermeable to urine so prevent ingress of toxins from urine
Which areas of the body have 3 layers constituting their MUSCULARIS EXTERNA?
- Stomach
- Bladder
- 3 layers are circular, oblique and longitudinal
Where in the body might you find stratified columnar epithelia?
Penile urethra
Describe the layers of the urethra wall
- Transitional epithelia (stratified columnar in the penile urethra)
- Lamina propria
- Muscularis externa (INNER LONGITUDINAL and OUTER CIRCULAR)
- Adventitia
Name the two types of membranes in the body
- Mucous
- Serous
