Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

BIOL 125 - Human Physiology > Week 22 > Flashcards

Week 22 Flashcards

1
Q

What are the main groups of neurotransmitters?

A

Acetylcholine
Biogenic amine
Amino acids
Peptides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

When was acetylcholine discovered?

A

1912

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How is acetylcholine synthesised? How is it broken down?

A

Synthesis:
Acetyl coA + Choline –> (by choline acetyl transferase) Acetylcholine

Breakdown:
Acetylcholine –> (by Acetylcholinesterase) Acetate + choline

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Acetylcholine binds to receptors on postsynaptic neurons. What are the two main types of Acetylcholine receptors?

A

Nicotinic (neuromuscular junction, brain, autonomic nerves)

Muscarinic (smooth muscle, exocrine glands, brain)​)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is a neuromuscular junction also known as?

A

Motor end plate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Nicotinic receptor agonists and antagonist?

A

Agonist: Nicotine (tobacco) - stimulatory

Antagonist: Curare - paralysis + poison

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Muscarinic receptor agonists and antagonist?

A

Agonist: Muscarine (toadstool)

Antagonist: Atropine (deadly nightshade)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is Alzheimer’s disease? What neuropathological changes occur?

A

First described by Dr. Alois Alzheimer it is the Progressive onset of dementia, including problems with memory ​

Neuropathological changes include loss of brain weight, enlargement of ventricles, numerous senile plaques and neurofibrillary tangles (NFTs) in the brain​

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Acetylcholine is important for memory and attention. What neurons die early in Alzheimer’s disease?

A

Cholinergic neurons

(Hence why drugs aim to boost acetylcholine to reduce symptoms, despite no direct cure)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

AChE inhibitors are one of only 2 approved drugs for the treatment of Alzheimer’s. What are examples of this?

A

donepezil (1997)​

rivastigmine (2000)​

galantamine (2001)

  • These drugs aim to reduce the breakdown of ACh in the synaptic cleft to improve ACh volume. Reducing cognitive decline.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How are catecholamines synthesised?

A

Synthesised from tyrosine, which is transported into the brain from the blood​.

Break down involves enzymes monoamine oxidase (MAO) and catechol 0-methyltransferase (COMT)​ in a process called catabolism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the two major families of dopamine receptors? What are these coupled to?

A

D1-like: D1 & D5​ (coupled to stimulatory g-protein)
D2-like: D2, D3, D4​ (coupled to inhibitory g-protein)

(all signal via adenylate cyclase and second messengers)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

When was Parkinson’s disease first described? What is it characterised by?

A

First described in 1817 by James Parkinson​

Mean age of onset ~ 60 yrs​
Affects 1-2% over 65 yrs ​

Characterised by: ​
muscle stiffness ​
slowness of movement ​
tremor at rest

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How does Parkinson’s disease occur? What is the % depletion of dopamine?

A

Occurs due to the Degeneration of dopaminergic (DA) neurons in the substantia nigra pars compacta and loss of dopamine in the caudate-putamen​

> 50% depletion of dopamine ​

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How are motor symptoms of Parkinson’s disease alleviated?

A

Treatment with L-dopa which is transported into brain and converted to dopamine​.

Administration of a peripherally active Dopa decarboxylase inhibitor prevents premature conversion of L-dopa to dopamine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What inhibitors prevent dopamine degradation to help relieve motor symptoms of Parkinson’s?

A

COMPT and MAO-B can also be given to inhibit dopamine degradation​

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How is serotonin synthesised and catabolised?

A

Synthesised from tryptophan by tryptophan hydroxylase and 5-hydroxytryptophan (5-HTP) decarboxylase​

Broken down to 5-hydroxyindoleactic acid (5-HIAA) by MonoAmineOxidase and aldehyde dehydrogenase ​

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

how does Serotonin (5-HT) signalling occur?

A

5-HT can bind to 14 different receptors which are all G-protein-coupled (not 5-HT3, as this is a ligand-gated ion channel)

Some receptors are excitatory, others inhibitory​

Action terminated mainly by reuptake from the synapse via the 5-HT transporter on the presynaptic neuron​

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How does SSRI act as a treatment for depression and anxiety?

A

Selective serotonin reuptake inhibitors (SSRIs) block the action of SERT = more serotonin at the synapse ​

Can help to reduce symptoms of depression, anxiety, OCD, PTSD, etc. ​

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are examples of SSRI drugs to treat depression and anxiety?

A

citalopram (Cipramil)​

escitalopram (Cipralex)​

fluoxetine (Prozac or Oxactin)​

paroxetine (Seroxat)​

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Amino acid transmitters: Glu, Asp, Gly, GABA are all non-essential amino acids, however which are excitatory, which are inhibatory?

A

All are non-essential amino acids (made in situ from glycolytic and citric acid cycle intermediates)​

Glutamate and aspartate are excitatory whereas glycine and GABA are inhibitory​

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

GABA receptors are inhibatory but what is the difference between GABA A and GABA B?

A

GABA A - Ionotropic receptor coupled to Cl- channel. This has modulatory binding sites for benzodiazepines, barbiturates, neurosteroids and ethanol. (Faster effect)

GABA B - Metabotropic receptor coupled to Ca2+ and K+ channels via G proteins and second messenger systems. (Slower effect)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Glutamate receptors are excitatory. What are examples of these receptors, what do they do?

A

NMDA receptor bind glutamate, glycine, Mg2+, Zn2+ and polyamines. Form channels that are permeable to cations (Ca2+ > Na+ and K+)​

Kainate and AMPA receptors interact only with glutamate and their specific agonists (Na+ and K+ > Ca2+) ​

mGluRs are G-protein coupled receptors and trigger a second messenger cascade (eight different types of mGluRs - an enhance or supress depending on binding)​

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

How do astrocytes buffer glutamate concentrations?

A

Glutamate is removed from the synapse by astrocyte uptake via excitatory amino acid transporters (EAAT)​

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
How do astrocytes buffer GABA concentrations
GABA is also taken up by astrocytes via GABA transporters (GAT) ​
26
How do astrocytes buffer both glutamate and GABA concentrations
Both glutamate and GABA are catabolysed in the astrocyte to glutamine, which is then transported to the neurons for re-use​
27
Astrocytes buffer NT concentrations and act as what?
Act as neurotransmission cleaners to prevent over or under stimulation of a neuron. Hence their importance in neuro signalling
28
What are GABA receptor agonists given for?
Treatment of seizures in epilepsy. Such as: Phenobarbital, Conazepam, Diazepam.
29
What does Memantine block? What does this treat?
Memantine blocks the Mg2+ binding-site on the glutamate NMDA receptor ​ Approved for use to treat Alzheimer’s disease in 2002​
30
What is the most common type of NT in the hypothalamus?
Peptide neurotransmitters
31
What neurotransmitter is synthesised as large e precursor proteins and transported to synaptic release site – activated by proteolytic cleavage​, and have a slow postsynaptic effect?
Peptide neurotransmitters
32
Peptide neurotransmitter actions are terminated by what? What are they often co-released with?
Actions terminated by extracellular proteases​ Often co-released with other classical transmitters
33
Peptide neurotransmitter examples include opioids, eg? Other examples?
endorphins, enkephalins and dynorphins​ Other examples are substance P, neurotensin, vasoactive intestinal peptide (VIP), etc.​
34
Other NT include purines, histamines and gases. How does nitric oxide act as a neurotransmitter?
Being a gas, NO is not stored in synaptic vesicles, but is made as required by an enzyme (nitric oxide synthase, NOS) from arginine.​ NO simply diffuses from nerve terminals into adjacent cells and forms covalent linkages to a multiplicity of targets, which may be enzymes or other targets.​ Inactivation presumably involves diffusion away.​
35
How long is the digestive tract?
GI tract Approx. 4.5 meters (in living), 9m (at autopsy)​
36
What are the four basic processes of the digestive system? Explain these processes briefly.
1. digestion​ physical and chemical breakdown of food​ 2. absorption​ transport of digestive end-products in to bloodstream​ 3. motility​ peristaltic activity of muscle, propelling food along GI tract​ Accessory glands (salivary glands, pancreas, liver, gall bladder)​ 4. secretion transport of digestive fluids into the GI tract​
37
What are the main digestive organs?
Mouth Pharynx (throat) Oesophagus Stomach Small intestine (duodenum, jejunum, ileum) Colon Rectum Anus
38
What are the different sphincters found across the digestive organs?
Upper oesophageal sphincter Lower oesophageal sphincter Pyloric sphincter Ileocecal sphincter Anal sphincter
39
What is the general structure of the GI tract?
Duct of accessory gland, Lumen, Mucosa (epithelium, 3 layers) Submucosa (connective tissue, blood and lymphatic vessels) Muscularis (Circular layer, longitudinal layer) Serosa (connective tissue) Nerve plexus - enteric nervous system
40
What does the Mucosa layer of the GI tract consist of?
Consists of mucous membrane, lamina propria (connective tissue, capillaries, nerves, lymphoid tissue) and muscularis mucosae ​
41
What is the mucosa membrane composed of?
Mucous membrane is composed of epithelial cells or enterocytes which include absorptive cells, exocrine cells, goblet cells (secrete mucus) and endocrine/exocrine cells (secrete hormones/enzymes)
42
How often is the mucosa replaced in the GI tract in a healthy adult?
~5 days
43
What glands are connected to the mouth?
Sublingual gland, Submandibular gland, Parotid gland All of which secrete saliva at 0.75-1.5 litres per day
44
What is saliva stimulated by? What are its functions?
Stimulated by autonomic nervous system​ Functions inculde: - Lubrication (mucus)​ - Buffering and diluting noxious substances​ - Antibiotic action (lysozyme, lactoferrin)​ - Taste​ - Cleans teeth​ - Fluoride, calcium uptake into teeth ​
45
What does saliva contain?
Contains salivary α-amylase (digests glycogen and starch) and lingual lipase
46
Features of the oesophagus?
Muscular tube (~ 25 cm long) connecting pharynx to the stomach​ Upper and lower esophageal sphincters usually closed, but backflow can occur causing heartburn​ Upper 1/3 has skeletal muscle​ Lower 2/3 has smooth muscle​
47
What are the different parts of the oesophagus?
Pharynx Larynx Upper oesophageal sphincter Oesophagus Lower oesophageal sphincter
48
The stomach can expand from 50ml to what?
1-2litres
49
What do the gastric glands (mucosa) contain that secrete HCl and pepsinogen?
contain parietal cells (secrete HCl) Chief cells (secrete pepsinogen)​
50
What are features of the stomach?
Can secrete 2 litres HCl/day (10 mM, pH 2!!)​ Pepsinogen (inactive zymogen) --> pepsin ​ Mucus (neck cells) and gastric lipase also secreted​ Intrinsic factor = glycoprotein required for absorption of vitamin B12 in the ileum ​ Rennin coagulates milk ​
51
In the stomach, the hormone gastrin and the vagus nerve trigger the release of what? What system is the vagus nerve apart of?
The hormone gastrin and the vagus nerve, trigger the release of pepsinogen and HCl​ The vagus nerve is part of the nervous system, involved in rest-and-digest​
52
Explain the mechanism of HCl secretion in the stomach?
H+ ions, made from CO2 and water by carbonic anhydrase (CA), are actively transported into the lumen in exchange for K+ ions​ Bicarbonate ions are exchanged for chloride ions, which diffuse into the lumen​ Nett result is the accumulation of HCl in the lumen​
53
What are zymogens?
Pre-enzymes (inactive form) and changes into the active enzyme where it meets what it breaks down. This is to protect the tissues that produce the enzyme.
54
Explain activation of pepsinogen?
Pepsinogen is not activated until it encounters HCl in the stomach​ The first 44 amino acids of pepsinogen are removed to generate pepsin​ Pepsin can then activate more pepsinogen​ Pepsin exhibits maximal activity at pH 2.0 and is inactive at ≥ pH 6.5 ​ Pepsin is an endopeptidase that starts to break internal peptide bonds of proteins to generate smaller fragments ​ Exopeptidases remove one amino acid at a time from either end of a polypeptide
55
Explain the activation of chymotrypsinogen?
Cleaved from its zymogen by trypsin into its active form, chymotrypsin. This then splits into 3 chains: A, B and C.
56
What are features of the small intestine?
Approx. 2.5 - 3 metres long​ First 30 cm = duodenum, then jejenum and ileum​ Duodenum receives chyme from stomach, enzymes from pancreas, and bile from liver & gallbladder ​ Responsible for digestion (duodenum) and absorption (all 3 regions) of all nutrients, water, vitamins, minerals​ Crypts of Lieberkuhn secrete copious amounts of bicarbonate-rich fluid to neutralise chyme from the stomach​
57
Where does most of the digestion of the small intestine occur?
duodenum and ileum
58
What do crypts of Lieberkuhn secrete? Where are they found?
Found in the small intestine, Crypts of Lieberkuhn secrete copious amounts of bicarbonate-rich fluid to neutralise chyme from the stomach​
59
What does the colon consist of?
the cecum, rectum, and anal canal. It also includes the appendix, which is attached to the cecum.​
60
In the colon, Crypts of Lieberkuhn are present, however what part of this structure isn't?
Villi
61
The colons two main principle function is what?
Principle site of water absorption​ (and some fats) Principle location of commensal microflora
62
How large is the colon?
The area of the large intestinal mucosa of an adult human is about 2 m2​
63
64
Pancreas and gall bladder are what type of glands? How do they pass enzymes/molecules into the duodenum to aid digestion?
Accessory glands, which aid digestion. They move items from them via the ampulla of vater via the sphincter of oddi, into the duodenum.
65
Name features of the pancreas?
~ 20cm long, weighs ~100g Digestive enzymes made by acinar cells (also make bicarbonate), released into duodenum. Zymogens made: chymotrypsin, trypsin, carboxypeptidase, elastase. Also makes pancreatic amylase (digests starch), lipase (digests fat), proteases, DNase, RNase Islets of Langerhans make hormones
66
What do acinar cells make?
Located in the pancreas, they make digestive enzymes and bicarbonate
67
Islets of Langerhans has three different cell types. What are these? What do they do?
β-cells make insulin - stimulates glucose glycogen​ α-cells make glucagon - stimulates glycogen glucose ​ d-cells make somatostatin - regulates digestion, absorption & release of other hormones​
68
Diabetes type 1 is an autoimmune disease caused by what?
Type 1 (early-onset, insulin-dependent) is an autoimmune disease caused by loss of insulin secretion from the islets of Langerhans​ Treated with insulin administration
69
Type 2 diabetes is associated with obesity, sedentary lifestyle and is due to?
(late-onset, non insulin-dependent) due initially to loss of responsiveness to insulin, followed by reduced insulin secretion​ At ‘pre-diabetes’ or ‘metabolic disorder’ stage, type 2 diabetes can be avoided through diet and exercise, but may require insulin in advanced stages​
70
Both types of diabetes cause an elevation in?
blood glucose​
71
Type 1 versus type 2 diabetes?
Type 1 = No insulin produced, so no uptake of glucose. Also an autoimmune response. Type 2 = Receptor doesn't recognise insulin, so no uptake of glucose. Also a lifestyle related illness.
72
Where does absorption mainly occur?
Small intestine - Duodenum and jejunum
73
Describe features of absorption in the digestive system?
Occurs mainly in the small intestine (duodenum and jejunum)​ Monosaccarides and amino acids are transported into blood capillaries of villi, then to the liver (via the hepatic portal vein)​ Fats are emulsified into fat droplets by the action of bile salts, they are then susceptible to digestion by pancreatic lipase​ Resulting long chain fatty acids and monoglycerides are converted into chylomicrons (small particles) which enter the lymphatic system (drains into blood in left subclavian vein in the neck) ​ Some small short-chain fatty acids are absorbed straight to the blood instead of the lymph
74
During absorption, fats are emulsified into fat droplets due to bile salts They are then susceptible to digestion by pancreatic lipase​, what does this entail?
Resulting long chain fatty acids and monoglycerides are converted into chylomicrons (small particles) which enter the lymphatic system (drains into blood in left subclavian vein in the neck) ​ Some small short-chain fatty acids are absorbed straight to the blood instead of the lymph​
75
How are chylomicrons formed?
Fatty acids and monoglycerides from fat digestion are absorbed and synthesised into triglycerides, which are then packed into chylomicrons​ (in the cell and its organelles) After exocytosis, chylomicrons enter the lacteals and into the lymphatic system​
76
What are microbiota?
“Ecological communities of commensal, symbiotic and pathogenic microorganisms”
77
Where is the highest site of microbiota?
Colon is the site of highest microbiota concentration at ~1012 ml-1​ Includes bacteria, archaea, protists, fungi and viruses​
78
What are the predominant phyla of microbiota?
Predominant Phyla: Bacteriodetes, Firmicutes, Actinobacteria and Proteobacteria
79
What are the main type of microbiota found in humans?
Bacteria represent between 300 and 1000 different species. ​ 99% of the bacteria come from about 30 or 40 species.​
80
Diet influences presence and abundance of bacteria in the microbiota found in our digestive system. What do they predominantly digest?
Fibre in the colon Producing Metabolites including: Vitamin K, Butyrate (fatty acid), thiamine, folate, biotin, riboflavin, and panthothenic acid.​
81
Our ability to digest, produce and absorb nutrients is influences by what?
Microbiota
82
Microbiota play a key role in our digestion. What do they modulate that has a role in metabolic syndrome development and obesity?
Fasting induced adipocyte factor (FIAF) expression/activation modulated by microbiota.
83
What does our lymphatic system aid in terms of digestion?
The thoracic duct drains into the left subclavian vein​ Mesenteric lymph vessels drain from the intestine. Nutrients, water, chylomicrons from intestinal absorption of dietary fat and lipids​ Helps to return surplus plasma filtered by capillaries back into the blood vessels – water balance​
84
How are Monosaccharides, amino acids, electrolytes, water, absorbed from the intestines and transported to the liver?
Via mesenteric veins and the hepatic portal vein​ They can then enter the general circulation via the hepatic vein​ Drugs given orally must survive ‘first pass’ through the liver ​
85
What does the gallbladder store?
Stores bile, which is produced in the liver. Can produce bile salts, and release them into the duodenum, to emulsify fats.
86
Describe features of insulin?
Proinsulin has 86 amino acids, To make insulin, 4 amino acids are removed leaving the A and B chains, plus the C-peptide.

BIOL 125 - Human Physiology (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions