BIOL122 Human Biological Science 2 Assignment Sample

Case study 1 part 1

Q.1. Conditions identified

1. Depression,

2. Dementia

a. Depression signs and symptoms

1. Loss of interest and loss of pleasure in activities

2. Mood swings

b. Dementia signs and symptoms

1. Memory problems

2. Mental confusion

Depression Pathophysiology

It has many theories which propose many mechanisms based on monoamine systems, circadian rhythm, immunological dysfunction.

Monoamine theory proposes that insufficient level or activity of monoamine neurotransmitters like dopamine, serotonin, and epinephrine causes depression. Normal levels of serotonin are associated with mood and behaviour regulation, sleep and digestion; norepinephrine is associated with fight or flight response; and dopamine is associated with movement, pleasure, and motivation.

Disorders of the immune system may also induce distress in different causes and events by an irregular immune response. The theory of Depression being an inflammatory condition is becoming common. It is ascribed to the fact that the levels of inflammatory markers such as interleukin, C-reactive protein, etc. are documented to be elevated in depressed patients.

Delayed circadian rhythm has been associated with depressed patients. Melatonin, a hormone secreted by the pineal gland in a circadian fashion, controls the rhythm of different biological parameters, such as body temperature, cortisol secretion and sleep cycles, has decreased levels in depression.

Alzheimer’s Pathophysiology

This disease attacks nerve cells and causes changes in proteins of the nerve cells. It has two characteristics effect; first clumps of protein form around the brain cells called amyloid plaques and second neuro fibres inside neurons also get clumped called intracellular neurofibrillary tangles (NFT). Thus, there is progressive neuron loss in Alzheimer’s resulting in memory, function and cognition decline.

The exact cause of Alzheimer's is unknown. There are various factors proposed like neurochemical factors (acetylcholine levels decrease), oxidative stress due to genetic and immunological reasons, and toxins due to environmental factors

Q.2.

Pharmacodynamics of Drugs

Fluoxetine for Depression

Fluoxetine, act as a selective serotonin reuptake inhibitor (SSRI) antidepressant which slows serotonin reuptake, allowing serotonin to remain longer when released. Therefore, the levels of serotonin are maintained. Serotonin helps in the regulation of mood and behaviour

Cholinesterase Inhibitors for Alzheimer’s

They are also known as anticholinesterase, functions by preventing the neurotransmitter acetylcholine from breaking down. This increases the amount of acetylcholine in the synaptic cleft which is the gap between nerve synapses. Acetylcholine helps in the transmission of the nerve impulse. In Alzheimer’s this transmission is impaired therefore cholinesterase inhibitors help by increasing communication between nerve cells.

Q.3.

Pharmacokinetics

Fluoxetine is a highly bioavailable drug by oral route within 6–8 hours. It is bound to albumin and alpha glycoprotein in plasma. It is converted into its metabolite form norfluoxetine. Both fluoxetine and norfluoxetine are very slowly eliminated from the body. Age does not affect its

pharmacokinetics so it is found suitable for older people. It can interact with other serotonin uptake inhibitors and antipsychotics and can increase their plasma concentration; therefore, it is required to be used cautiously with these drugs.

Fluoxetine can reduce the metabolism of other drugs due to its effect on hepatic enzymes. So other drugs may be less bioavailable. Fluoxetine can reduce the effect of other drugs like cholinesterase inhibitors and diazepam. So, it should be watched and drug regimen changed if symptoms do not improve or worsen.

Q.4.

There are several signs of alcohol dependency present in the case of Mary-Lou. She is using alcohol to sleep and to be happy. She started drinking alcohol moderately but has now drinking heavily in the night as well as day time. She is relying on alcohol to better her mood. The doctor also prescribed her diazepam to manage her withdrawal symptoms.

Psychological dependence on alcohol is the first stage of alcohol addiction. In this body is not relying on alcohol to function yet but there is a strong mental desire to drink. It starts by feeling good on drinking alcohol and may or may not progress to physical dependence. Always thinking about alcohol, not taking interest in daily activities, are some of the symptoms of psychological dependence.

The physical dependence on alcohol is when the body is always craving for alcohol as it has adjusted to the levels of alcohol. On not getting alcohol withdrawal symptoms to appear like irritability, panic, insomnia, inability to focus, high blood pressure, etc.

In Mary-Lou some of the symptoms of psychological symptoms are there as a strong desire to drink alcohol, feeling good on drinking alcohol. Also, these symptoms are progressed to not able to sleep without alcohol, increased alcohol intake which suggests her becoming addicted to alcohol for physical functioning.

Case study 1 part 2

Q.5.

Crepitus is typically caused by rubbing together of rough joint cartilages or bones which result in pain. This condition is a result of osteoarthritis.

Pathophysiology of Osteoarthritis (OA)

OA is mainly a degenerative cartilage disease. Cartilage is composed of solid type 2 collagen and proteoglycans, and cellular chondrocytes in a hard gel-like matrix form Under normal situation this matrix is always going through remodelling process of enzymatic activities. There exists a balance between degradative and synthesis activities of enzymes. In OA cartilage, the degrading activities are enhanced which causes loss of collagen and proteoglycans. in the matrix. The main enzymes which cause collage loss are the matrix metalloproteinases (MMPs). These enzymes are inhibited by MMP inhibitors, but in OA, MMP inhibitors are simply overcome by MMPs. The primary candidate held responsible for activating MMPs is inflammatory cytokine interleukin-1 (IL-1). Therefore, in a nutshell, the inflammatory activities of IL-1 and MMPs are what appear to be responsible for cartilage degeneration and OA. The characteristic signs and symptoms of osteoarthritis include pain, stiffness in joints, tenderness in joints, flexibility loss in joint, swelling, grating sensation.

Q.6.

Difference Between Aetiology of Osteoarthritis and Rheumatoid Arthritis

Osteoarthritis (OA) is caused by degeneration of cartilage due to normal wear and tear, whereas rheumatoid arthritis (RA) is caused by an autoimmune disorder in which the immune system itself attacks the cartilage. In OA the symptoms appear gradually while in RA they arise quickly and also gets worse quickly in a few weeks. In OA many times only one side of the body which is subject to more stress is affected whereas in RA both sides joints are affected. OA generally happens to older people whereas RA can occur at any age.

Q.7.

Fracture healing happens by multiple anabolic(building) and catabolic(destroying) processes. The first stage is the inflammatory phase in which T cells and macrophages take part, that removes dead cells and signals osteochondral stem cells for differentiation into progenitor stem cells. The second stage is bone formation in which progenitor cells start soft callus formation by changing into chondrocytes and finally into a hard callus, where chondrocytes are replaced by osteoblast. The third is bone remodelling in which callus is decreased in size, vascularization completes by re-establishing blood vessels and osteoblastic and osteoclastic processes remodel the bone.

The stem cells and immune cells are impacted by age-related changes which negatively affects fracture healing. In the first phase of inflammation T-cells and macrophages take part, which is affected negatively by age. In the second phase, Osteochondral stem cells are required which are decreased in quantity as the age progresses. Finally, vascularization is also age-dependent.

Thus, Mary’s fracture will take longer to heal than a person half her age. Also, hip fractures are dangerous at her age as it can give rise to complications due to prolonged immobility. For example, there is a risk of blood clot formation, bedsores, and infections in the urinary tract.

Q.8.

Dexa scan is used for measuring bone mineral density. In this, the T-score tells how much bone density is higher or lower than a healthy adult of 30 years ago. T-score of -1.0 or above is for a healthy adult. A T-score between -1 to -2.5 shows low mineral density or osteopenia. T-score less than -2.5 is an indicator of osteoporosis. Since Mary’s score is -3.0, it suggests she is suffering from osteoporosis.

Pathogenesis of Osteoporosis

With age bone mass decreases, the level at which bone mass reduces so much that there is a significantly greater risk of fracture is called osteoporosis. Imbalance in bone formation and bone reabsorption causes osteoporosis. Bone cells osteoblasts control bone deposition and osteoclasts control bone resorption.

Bone loss happens due to many reasons like genetic factors, illnesses, sex hormone deficiency after menopause in women and with aging in men.

Bisphosphonate therapy is helpful as it inhibits the activity of osteoclasts. On administration, bisphosphonate binds with bone and cause inhibition of osteoclast activity. It also decreases the number of osteoclasts by causing its apoptosis. This results in decreased bone resorptive process and hence increases bone density and strength of bone.

Case study 2

Q.9.

In Hilda’s case, her asthma allergens include cold temperature, pollen, smoky environments and respiratory infections as she was working in the garden in cold spring day, pollens and cold temperature appear to be what triggered her asthma attack.

Asthma is a chronic respiratory inflammatory condition. There are many factors which contribute to asthma development like, genetics, allergies, respiratory infections, environment. When an allergen triggers the respiratory airways, they become inflamed, restricted and started filling with mucus.

When an allergen comes in contact with Immunoglobin E bound mast cells, which are part of the immune system, they release histamines, cytokines, and prostaglandins. They cause contraction of the smooth muscle of airway called bronchospasm and narrowing of airway which is called bronchoconstriction, thus restricting the airflow. As inflammation further progresses, hypersecretion of mucus, oedema and changes in the structure of airway smooth muscle can happen.

This causes breathing difficulty in the patient. Respiratory and heart rate is increased to compensate for oxygen demand. In extreme conditions, dyspnoea and hypoxia can develop.

Q.10.

In Hilda’s case due to an asthma attack, she was having difficulty in breathing, wheezing, cough, and cyanosis (bluish colour) of lips. Asthma causes respiratory distress by airway constriction. It is triggered by allergens which cause inflammatory response resulting in spasm and narrowing of airways. The wheezing sound indicates a narrowing of the airway. Hypersecretion of mucus and airway changes further restricts air exchange. This restriction prevents effective air exchange, as a result, the oxygen demand of the body is not met. To try and take more oxygen, respiratory and heart rate increases. In the case of hypoxia when the oxygen saturation levels are further reduced cyanosis is observed. Cyanosis is the blue colour observed when haemoglobin in blood is deoxygenated.

Q.11.

For Hilda’s asthma Ventolin is prescribed. This drug works by dilating the smooth muscles of airway and also by inhibiting inflammatory mast cells in asthmatic patients. It begins by blocking the beta 2 androgenic receptors, which are present in the bronchial smooth muscles. This causes a signalling mechanism whereby ultimately calcium ion concentration in the muscle cells decreases and they relax. This relaxation provides increase opening for air exchange, thus helps in relieving the symptoms of breath shortage. Ventolin also inhibits the inflammatory activity of mast cells, further helping in reducing the allergic reaction.

Q.12.

In Hilda’s case, appropriate precautions are taken to minimize her chances of contracting the novel coronavirus. All coronavirus patients are isolated in private rooms, and all healthcare staff practice proper hand hygiene and use personal protective equipment. Novel coronavirus causes Covid-19 disease which is highly contagious, it is spread by droplets of saliva or nose discharge when an infected person coughs or sneezes. From this droplets coronavirus enters the nose or mouth of an uninfected person, when he breathes It is also spread by fomites which are articles on which coronavirus is transferred due to coughing, sneezing or touching by an infected person. When a non-infected person touches his nose or mouth after touching these articles, this coronavirus may enter his nostrils or mouth and cause infection.

So, to prevent the infection from spreading proper hand hygiene is a must. This reduces the chance of infection entering the mouth or nose by touching. Wearing masks and personal protective equipment also reduce the chances of spread of coronavirus. For breaking the chain of infection, social distancing should be practised as it prevents direct contact with infected people.

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