Physiology

Question 1

What are the 3 forms of action potential?

Answer 1

1. Neuronal
2. Muscle
3. Cardiac

Question 2

What generates the neuronal action potential?

Answer 2

Rapid movement of sodium (Na) into the cell

Question 3

What is normal resting membrane potential?

Answer 3

-70mV

Question 4

What is the name of conduction in which the action potential ‘jumps’ between nodes of Ranvier?

Answer 4

Saltatory conduction

Question 5

At what point in development does myelination begin?

Answer 5

6 months into fetal development

Question 6

When in development is myelination complete?

Answer 6

Up to 2 years after birth; motor pathways amongst last to be fully myelinated

Question 7

Name the major excitatory neurotransmitter in the CNS

Answer 7

Glutamate

Question 8

Name the major inhibitory neurotransmitter in the CNS

Answer 8

GABA (gamma-amino-butyric acid)

Question 9

What are the main neurotransmitters of the PNS?

Answer 9

Acetylcholine and noradrenaline

Question 10

How is glutamate produced?

Answer 10

By product of the Kreb’s cycle

Question 11

How do neuromodulators generally act?

Answer 11

Via G-protein coupled receptors to modulate receptor sensitivity to neurotransmitters by activating second messenger cascades in the post synaptic cell.

Question 12

What is Wernicke-Korsakoff syndrome?

Answer 12

Disorder caused by thiamine (vitamine B1) deficiency associated with degeneration of the mamillary bodies.
Manifests as balance and movement issues, confusion and eye problems (e.g. diplopia)

Question 13

What is ageing?

Answer 13

Characterised as the gradual decline in normal physiological functions and physiological integrity in a time-dependent manner, affecting all biological systems, such as molecular interactions, cellular functions, tissue structure and systemic physiological homeostasis.
It is a natural process.

Question 14

What is gerontology?

Answer 14

The scientific study of the process and problems of ageing.

Question 15

What age is ‘young-old’?

Answer 15

People in their 60s and early 70s who are active and healthy

Question 16

What age is ‘old’?

Answer 16

People in their 70s and 80s who have chronic illnesses and are slowing down due to symptoms

Question 17

What age is ‘old-old or oldest-old’?

Answer 17

People that are often sick, disabled, and perhaps even nearing death

Question 18

Name some diseases and conditions are associated with ageing?

Answer 18

• Neurodegenerative diseases (dementia)
• Osteoporosis (falls)
• Hearning loss
• Incontinence
• Cancer
• Diabetes
• Arthirits

(Age-associated diseases)

Question 19

Define chronic conditions (ageing lecture)

Answer 19

Those that persist and require on-going management over a period of years or decades.
Not transmissible directly from one person to another.

Question 20

Define lifespan

Answer 20

The maximum length of time an organism is expected or known to survive (potential: 125 years in humans)

Question 21

Define life expectancy

Answer 21

The average length of time an organism is expected to live (~80 years for UK)
(The average of lifespan)

Question 22

Define healthspan

Answer 22

The percentage of an individuals life during which they are generally in good health

Question 23

What are the 3 categories within which the nine cellular hallmarks of ageing fall?

Answer 23

1. Primary hallmarks (cause of damage)
2. Antagonistic hallmarks (resposne to damage - can be positive or negative)
3. Integrative hallmarks (primary and antagonistic together)

Question 24

Name the 4 primary hallmarks of ageing

Answer 24

1. Genomic instability
2. Telomere attrition
3. Epigenetic alteration
4. Loss of proteostasis

Question 25

What are lamins?

Answer 25

Lamins are proteins providing structural function and transcriptional regulation in the cell nucleus.

Question 26

What does free radical theory of ageing state?

Answer 26

Caused by accumulation of damage inflicted by reactive oxygen species (ROS)

Question 27

What are telomeres?

Answer 27

Repetitive nucleotide sequences at the end of chromosomes; role is to protect the end of chromosomes from decay and fusion with other chromosomes.

Question 28

What are epigenetics?

Answer 28

Factors causing a heritable change in gene expression in the absence of a change in the DNA sequence itself

Question 29

What is proteostasis?

Answer 29

Also known as protein homeostasis; refers to the process by which cells control the abundance and folding (3D functional structure) of the proteome

Question 30

Describe why loss of proteostasis affects ageing

Answer 30

In young/healthy cells, misfolded protein load is disposed of by protein quality control (PQC) systems In ageing cells, the load may overwhelm the PQC capacity, resulting in accumulation of misfolded proteins and loss of protein homeostasis (proteostasis) Appearance of non-native protein aggregates is a common feature of aged cells and certain age-assocaited diseases, such as Alzheimer's/Parkinson's

Question 31

What is cellular senescence?

Answer 31

Process that imposes permanent proliferative arrest on cells in response to various stressors, leading to formation of senescent cells with specific phenotypic characteristics

Question 32

What is stem or progenitor cell exhaustion?

Answer 32

Inability of stem cells or progenitor cells to replenish the tissue or an organism (stem cell theory of ageing)

Question 33

Name 4 structural changes that happen with ageing in the CNS

Answer 33

1. Decline in brain mass and weight 2. Fewer synaptic connections and nerve cells 3. Reduced cerebral blood flow 4. Altered neurotransmitters e.g. decreased dopamine, serotonin

Question 34

Name the functional changes that happen with ageing in the CNS

Answer 34

1. Intellect - slowing in central processing (but maintained until at least 80) 2. Verbal skills (gradual decrease in vocabulary, increased errors; normally maintained until 70) 3. Mental activity (difficulty learning, especially languages and forgetfulness)

Question 35

Name 5 strucutral/functional changes in ageing within the PNS

Answer 35

1. Decreased spinal motor neurons 2. Axon atrophy 3. Nerve conduction slows (reduction in myelin) 4. Reduced vibratory sensation (especially in feet) 5. Reduced thermal sensitivity (pain and temp are small unmyelinated) 6. Loss of myelinated axons

Question 36

Name 4 structural changes in the kidneys with ageing

Answer 36

1. Kidney size (weight and length) decreases 2. Nephron size and number decreases 3. Glomerular simplification (reduced number of glomerular capillary loops) 4. Glomerular basement membrane thickening

Question 37

Name 3 functional changes in the kidneys in ageing

Answer 37

1. Glomerular filtration rate declines from 4th decade onwards 2. Reduced kidney muscle mass results in reduction in creatinine clearance, leading to reduction in daily urinary creatinine excretion 3. Renal blood flow declines 10% per decade after the 4th decade

Question 38

Name 4 structural changes to bones with ageing

Answer 38

1. Bone density reduces 2. Slower healing of fractions 3. Reduced bone remodelling 4. Reduced osteoclast bone formation

Question 39

Define sarcopenia

Answer 39

The degenerative loss of skeletal muscle mass, quality, and strength associated with ageing

Question 40

What is stem or progenitor cell exhaustion?

Answer 40

Inability ot stem cells or progenitor cells to replenish the tissue of an organism (stem cell theory of ageing) Can be caused by excessive proliferation, leading to exhaustion and premature ageing

Question 41

Describe 3 cardiovascular changes with ageing

Answer 41

1. Thickening and stiffening of the large arteries (due to collagen deposition and loss of elastic fibres in the medial layer) - leads to increased systolic blood pressure 2. Decline in maximum aerobic capacity (VO2max) 3. Decline in cardiovascular performance during exercise (due to deficits in cardiac b-adrenergic receptor density) Ageing can increase the risk of left ventricular hypertrophy, CHF and atrial fibrillation

Question 42

Name 4 changes in gastrointestinal structure with ageing

Answer 42

1. Decreased liver size and blood flow 2. Decrease in effective colonic contractions 3. Reduced pancreatic mass and enzyme reserve 4. Impaired response to gastric mucosal injury

Question 43

Name 4 changes in gastrointestinal function with ageing

Answer 43

1. Reduced stomach acid production 2. Slowing of gastric emptying 3. Nutrition absorption decreases (Ca, Vitamin D) 4. Reduced tensile strength in muscle of colonic wall

Question 44

Describe changes in joints with ageing

Answer 44

- Reduced thickness of articular cartilage | - Increased stifness and brittleness of collagen

Question 45

Describe 4 changes to muscle with ageing

Answer 45

1. Muscle mass and strength declines with age 2. Increased percentage of type I fibres compared to type II 3. Decreased basal metaoblic rate with age 4. Increased fat deposits into muscles Sarcopenia is the degenerative loss of skeletal muscle mass, quality, and strength associated with ageing