Human Systems Overview Flashcards
Structure and layers of GI tract?
- mucosa (epithelium, lamina propria, muscularis mucosa)
- submucosa
- muscularis propria (inner circular, outer longitudinal)
- serosa
What is the string on skin under the tongue called?
Frenulum
What is the dangling thing at the back of the mouth?
Uvula
Where does the parotid gland open into the oral cavity?
Stensons duct opposite the second molar
Where do both the submandibular and sublingual glands open into the oral cavity?
Wharton’s duct under the tongue on the floor of the mouth
What nerve innervates the muscles of facial expression?
Facial nerve
What nerve innervates the muscles of mastication?
Mandibular branch of the trigeminal nerve
What are and where are the muscles of mastication?
What are the boundaries of the pharynx?
Base of skull to C6
What is the origin and insertion of the masseter?
- zygomatic arch
- angle of mandible
What is the only muscle which opens the mouth?
Lateral pterygoid
What is the origin and insertion of the temporalis?
- floor of temporal fossa
- coronoid process
What are tonsils made up of?
Lymphoid tissue
What are the main tonsils pairs?
- pharyngeal
- tubal
- palatine
^waldeyers ring - lingual tonsils
Does the oesophagus lie posterior or anterior to the trachea?
Posterior
What is the epithelium in the oral cavity and oesophagus?
Stratified squamous
What is the extra layer of muscularis propria in the stomach?
Innermost oblique
What is a common clinical diagnosis surrounding the oesophagus?
Barrett’s oesophagus due to metaplasia
What is dysphasia?
Difficulty swallowing
What do mucous cells secrete?
Alkaline mucous secretions
What do parietal cells secrete?
HCl and intrinsic factor
What do chief cells secrete?
Pepsinogen
What do G cells secrete?
Gastrin
What increases secretions by parietal cells?
Gastrin from G cells
What does intrinsic factor (parietal cells) do?
Increases B12 absorption
What converts pepsinogen to pepsin?
HCl from parietal cells
What is the epithelium in the nasal cavity?
Pseudo stratified ciliates epithelium
What epithelium is in the trachea?
Ciliated simple columnar
What type of epithelium lines alveoli?
Simple squamous
What are the parts of the stomach?
- cardia
- fundus
- body
- pylorus
What is the function of rugae?
Increase surface area
What are the three arteries which branch off if the coeliac trunk?
- left gastric artery
- common hepatic artery
- splenic artery
What are the branches off the common hepatic artery?
- right gastric artery
- gastroduodental artery
What are the branches of the splenic artery?
- short gastric
- left gastroepiploic
What is the branch off the gastroduodenal artery?
right gastroepiploic
What are the two veins in which all veins off the stomach drain to?
- splenic vein
- superior mesenteric vein
What is the primary site of absorption and digestion?
The small intestine
What is the function of villi?
Increase surface area for absorption
Where are burners glands located and what is there function?
Duodenum
- secrete alkaline mucous to protect
Where is bile produced?
The liver
Where is bile stored and concentrated?
The gallbladder
What is the sphincter of oddi?
Muscular valve controlling pancreatic/bile secretions surrounding the major duodenal papilla
What is CCK?
Cholecystokinin
What are brush border enzymes and their function?
Found in the jejunum
- aid digestion
What are peters patches and their function?
Found in the ileum
- keep intestinal flora levels correct
What are the three parts of the small intestine?
- duodenum
- jejunum
- ileum
What is meckel’s diverticulum?
Clinical diagnosis surrounding the small intestine
- 2 years old
- 2 inches long
- 2 types of mucosa
- 2% of the population
What are the two turns in the large intestine called?
- hepatic flexure
- splenic flexure
What are taeniae coli?
3 longitudinal bands of smooth muscle in the large intestine which aid contraction
What are haustra?
Pouches of peritoneum filled with fat on the large intestine
What are cells which are found in abundance in the large intestine?
Goblet cells
What iso the function of intestinal flora?
Ferment fibre and lipids, producing gases and synthesise vit B and vit K
What is the function of vit K?
Blood clotting
What is the name for movement of food through the GI tract?
Peristalsis
Which enzymes are produced in the pancreas?
Amylase
Lipase
Trypsin
Nucleases
What is the other secretion of the pancreas which isn’t an enzyme?
Bicarbonate
What is the function of amylase?
Breaks down starch
What is the function of lipase?
Breaks down fat
What is the function of trypsin?
Breaks down proteins
What is the function of nucleases?
Breaks down nucleotides
What is the function of bicarbonate?
Neutralises gastric acid
What % of the pancreas is exocrine?
99%
What are the hormones produces by the endocrine pancreas?
Insulin (beta cells) increase glucose absorption
Glucagon (alpha cells) release of glucose
Somatostatin (delta cells) slows digestion
What is a symptom of obstructive jaundice?
Yellow skin from bilirubin- blocked bile duct
What is bilirubin?
Found in bile- made up of broken down RBSs
What is the largest gland in the body?
The liver
What is the function of the hepatic ducts?
Carry bile from the liver to the gallbladder
What is the function of the hepatic vein?
Carries blood to the liver from the GI tract
What happens to bilirubin?
Removed from the body by the liver
What is GIP?
Gastric inhibitory peptide from duodenum
- inhibits acid secretion
- increases insulin
What is secretin?
- reduces gastric acid secretion
- increases bicarbonate secretion from pancreas
- produced in duodenum
What CN provides sensation to the posterior 1/3 of the tongue?
Glossopharyngeal nerve IX
What CN provides sensation to the anterior 2/3 of the tongue?
Hypoglossal XII
What is the control of the internal anal sphincter?
Autonomic- Parasympathetic
What is the control of the external anal sphincter?
Somatic
What is VIP?
Vasoactive intestinal polypeptide
What is an unfertilised egg called?
Ovum
What is a fertilised egg called?
Zygote
When is a human classed as an embryo?
0-9 weeks
What is a 16 cell embryology stage?
Morula- 4-6 days
What is a 32 cell embryology stage?
Blastocyst- 6-10 days
What is the outer cells in the blastocyst?
Trophoblast- will become the placenta
What does the epiblast layer of the bilaminar embryonic disc give rise to?
- ectoderm
- mesoderm
- endoderm
What does the hypoblast layer of the bilaminar embryonic disk give rise to?
- endoderm
- extra embryonic mesoderm
What occurs in the gastrulation phase of embryology?
- third layer of cells arises- mesoderm
What does the neural tube give rise to?
The CNS
What is a common embryological diagnosis during organogenesis?
Spina bifida- neural groove persists
What does ectoderm give rise to?
- skin
- CNS
- enamel
- mucous membranes
What does mesoderm give rise to?
- connective tissue
- muscle
- blood vessels
- kidneys
- reproductive system
What does the endoderm give rise to?
- alimentary system
- respiratory system
What does the neural crest/ectomesenchyme give rise to?
- PNS
- melanocytes
- remaining dental tissues (not enamel)
- adrenal medulla
Function of astrocytes?
Neuroglia, blood brain barrier CNS
Function of microglia?
Neuroglia, phagocytes CNS
Function of oligodendrocytes?
Neuroglia, myelin formation in CNS
Function of ependymal cells?
Neuroglia, cerebrospinal fluid PNS
Function of Schwann cells?
Neuroglia, myelin formation PNS
What’s a dermatome?
Area of sensory input
What is a myotome?
Area of motor output
Spinal nerves?
- 8 cervical
- 12 thoracic
- 5 lumbar
- 5 sacral
- 1 coccygeal
Cranial nerves
- olfactory
- optic
- oculomotor
- trochlear
- trigeminal
- abducens
- facial
- vestibulochoclear
- glossopharyngeal
- vagus
- accessory
- hypoglossal
What are afferents?
Sensory nerves
What are efferents?
Motor nerves
What is the function of dendrites?
Receive inputs from other neurons
What maintains the resting membrane potential?
Outwards diffusion of potassium ions and sodium potassium pump
How does local anaesthetic work?
Blocks sodium channels and stops nerve conduction
Action potential
- stimulus
- small depolarisation of membrane
- if reaches -55mV (threshold) sodium voltage gated channels open
- large depolarisation due to influx of sodium
- peak voltage reached- 35mV
- sodium voltage gated channels close
- voltage gated potassium channels open
- potassium flows out the cell giving depolarisation
- slight overshoot of resting potential
- resting potential reestablished
What increases the speed of an action potential?
- larger axon diameter
- myelination
What are nodes of ranvier?
Breaks in myelin to allow ion flow
Events at a synapse- excitatory
- AP in presynaptic cell opens voltage gated calcium ions- calcium influx
- depolarisation of pre synaptic cell
- triggers vesicles containing neurotransmitters to secrete into the synaptic cleft
- neurotransmitter binds to receptors on post synaptic cell causing a graded potential
- AP in post synaptic cell
- repuptake and enzyme degradation of remaining neurotransmitter in synaptic cleft to inactivate
What is an inhibitory post synaptic response?
The neurotransmitter causes hyperpolarisation
What is the name of the neurotransmitter at a neuromuscular junction?
Acetylcholine
What is the name for the release of neurotransmitter into the synaptic cleft?
Exocytosis
What are the nerves involved in the PNS?
CN 3,7,9,10 S2,3,4
What nerves are involved with the SNS?
T1-L2
Which branch of the ANS controls constriction/dilation of blood vessels?
Sympathetic (alpha=constriction, beta=dilation)