What is the lamina propria?
-Thin layer of connective tissue
What are the layers of a mucous membrane?
- Epithelium lining the lumen
- Lamina propria
- Muscularis mucosa
What is muscularis mucosa?
-Smooth muscle in mucous membranes
What structures do mucous membranes line?
- Alimentary tract
- Respiratory tract
- Urinary tract
- I.e. internal tubes which open to the exterior
What are serous membranes?
- Two part membranes which line closed body cavities which envelope viscera
- I.e. peritoneum, pericardium, pleural sacs
What is the function of serous membranes?
-Secrete lubricating fluid promoting friction-free movement of the viscera they surround
What type of epithelium are serous membranes?
-Simple squamous epithelium (mesothelium)
-How to serosae come to surround viscera?
- The viscera invaginate into the serosae becomming surrounded.
- The membrane closest to the organ is the visceral membrane
- The opposing membrane is the periatal membrane
What makes up the alimentary canal?
- Oesophagus
- Stomach
- Duodenum, jejenum, ileum
- Colon
- Rectum
What are the layers of the alimentary tract wall?
- Mucosa
- Submucosa
- Muscularis externa
- Serosae
What is the mucosa made up of?
- Epithelia
- Lamina propria
- Muscularis mucosa
What is the immune adaption of the mucosa of the ileum?
-Peyers patches (aggregations of lymphocytes) in the lamina propria
What is the adaption of the mucosa in the stomach?
-Rugae (folds of gastric mucosa)
What is an adaption of the jejenum?
- Pilcae circulares (folds of mucosa/submucosa into lumen) which have villi which have microvilli
- Greatly increase surface area
What is an adaption of the colon mucosa?
- Have microvilli
- Have crypts of lieberkuhn which secrete mucus
What is submucosa?
- Connective tissue which lies underneath the mucosa
- Contains glands, blood vessels and nerves
What is the muscularis externa?
- Smooth muscle which surrounds submucosa
- Has two layers - inner circular layer and outer longitudial layer
- surrounded by serosae
What is the function of the muscularis externa in the alimentary canal?
-Peristaltic waves to move lumen contents along
What is adventitia and when is it present?
- Thin layer of connective tissue
- Present when there is no invagination of viscera into the pericardium, pleural sac or peritoneum
List the conducting portion and the respiratory portions of the respiratory tract?
- Conducting portion - nasal canal, nasopharynx, oropharynx, larynx and trachea
- Respiratory portion - bronchi, bronchioles, lung, alveolar ducts, alveoli and diaphragm
What is the epithelium of the respiratory tract?
-Pseudostratified, ciliated epithelia
What is the epithelium of the oesophagus?
-Stratified squamous non-keratinised
What is the epithelium of the majority of the alimentary tract?
-Simple columnar
What are the cell types in the alveoli?
- Type 1 squamous (90%)
- Type 2 cuboidal which secrete surfactant
What are alveoli surrounded by?
-A basketwork of capillaries and elastic fibres
What immune cell type lines the alveoli?
-Numerous macrophages
List the layers of the respiratory tract walls
- Mucosa
- Submucosa
- muscularis externa
- serosae/adventitia
Which section of the respiratory tract has adventitia?
-Trachea
What type of glands are in the submucosa of the trachea?
-seromucus
What unicellular glands are present in the respiratory tract and upto what point?
- Goblet cells
- Upto bronchioles as the lumen gets narrow, mucus would block it.
What is the function of the trachealis muscle and where is it located?
- At the back of the trachea, anterior to the oesophagus
- Can open and close the trachea to an extent
Describe the hyaline cartilage of the trachea and state its purpose
- C shaped rings
- to keep the airways open
-Upto what point in the respiratory tract is cartilage found?
-Down to the bronchioles
-What keeps the bronchioles open?
-The surrounding alveoli
What happens to the hyaline cartilage of the respiratory tract with age?
-Partly transforms to bone
What makes up the urinary tract?
-Kidney, ureter, bladder, urethra
What epithelium is present in the bladder, ureter and urethra and what is its function?
- Transitional epithelium
- Distensibility and protection from toxic chemicals
What are the layers of the mucosa of the bladder?
- Transitional Epithelium
- lamina propria
- no muscularis mucosae
Why is the bladder impermeable to urine?
- Thick PM
- Intracellular tight junctions
What adaption does the muscularis externa of the bladder have?
-Has three layers instead of two
Does the bladder, ureter and urethra have adventitia or serosa?
-Adventitia
Why are females more prone to urinary tract infections
- Female urethra 1.5 inches
- Male urethra 8 inches
What epithelial cells are found in the penile urethra?
-Stratified columnar epithelia for blood flow for erection
