Immunity-Defense

This refers to the body's ability to prevent the invasion of pathogens and resist harmful microorganisms.

Bacteria, Viruses and Fungi can all be classified as pathogens, because they're the harmful foreign micro organisms that cause harm and disease to the human body. Whenever they're present in the body, the immune system responds by producing antibodies which detect them and eventually fight them off.

Immunity Specifications

📍Non-specific defense responses - 1st and 2nd lines of defense

🔅 Nonspecific defenses are general attack responses. The response is always the same no matter who the "invader" is.

🔅1st lines of defense: The body's first line of defense are structural, mechanical and chemical defense responses on internal and external surfaces of the body. These include;

a). Skin and mucous membranes (epithelial surface tissues)

i). Cells are tightly joined together, preventing bacteria from invading deeper tissues.(If you have an open wound, you better clean it and ensure its well covered or else it'll breed bacteria).

ii). Sloughing of dead cells prevents microbial population from continually increasing.

iii). The protein keratin, fills the cells in the outer layers of the epidermis. These cells then contain little water, making the skin dry and inhospitable to many microbes.

iv). Ciliated, mucous membranes (eg in the respiratory tract) trap microbes, dust in mucous. The cilia move mucous toward mouth, where it is coughed up and swallowed.

b). Normal flora

This refers to the microbial family, majorly bacteria, that colonies on the skin and mucus membrane of the human body. These flora occur naturally on/in the human body.

▪️ Normal bacterial inhabitants of the skin, gut and vagina (I.e. the "natives" )outcompete the "foreigners" for resources. Different mechanisms are usually involved in order for them to accomplish their mission.

▪️ Some normal bacteria produce acid from sugar fermentation, creating an acidic environment that keeps other populations in check- for example, lactic acid produced by bacteria in the vagina keep the yeast Candida albicans under control.

▪️ In the vagina, low estrogen concentrations in prepubertal and postmenopausal women result in a decrease in bacterial numbers in the vagina. This can lead to vaginal yeast infections.

▪️Yeast infections can also result from antibiotic treatments (mostly broad spectrum antibiotics kill the pathogen and the normal flora) and douching.

c). Movement of body fluids dislodges microbes

▪️ Some body fluids such as urine, tears and saliva sweep away microbes in their passages as they flow.

▪️ Also, peristalsis in digestive tract causes food and digestive juices to sweep microbes away.

d). Secretions

▪️ Tears, perspiration and saliva contain lysozyme, an enzyme that destroys the bacterial cell wall. This enzyme works as a protection against the foreign pathogens.

▪️ Perspiration also contains high concentrations of salt hence creating a hypertonic environment that is inhospitable to pathogens.

▪️ Bile, produced by the liver, also disrupts the bacterial cell wall. Bile is secreted into the small intestine to aid in the digestion of lipids. It passes from the small intestine into the colon and into feces. Through this, it helps in killing any harmful bacteria in the pathway.

▪️ Hydrochloric acid produced in the stomach (pH of the stomach is 2!). This condition is quite intolerable for pathogens to survive/

▪️ Fatty acids are contained in the oil secreted from oil glands in the skin. It makes the skin slightly acidic.

🔅2nd lines of defense: This deals with defense mechanisms that involves internal human body - i.e. what happens inside once the microbes get past the surface defenses.

▪️ It mostly involves the white blood cells, which usually belong in different groups as follows; Macrophages – phagocytic, eosinophils – phagocytic , neutrophils – phagocytic , basophils - release histamine and are involved in the inflammatory response and lymphocytes - has 3 types i.e. B cells, T cells and Natural Killer cells.

📍Specific defense responses- 3rd line defense response

🔅The Immune System

▪️When general attack responses are not enough to stop the spread of an invader & illness follows, three types of white blood cells (macrophages, T cells and B cells) will counterattack.

▪️Their interactions are the basis of the immune system. Two important characteristics of the immune system are its specificity and its memory.

🔅White Blood Cells Involved in Specific defense responses are:

a). Macrophages - These are phagocytic. They are involved in inflammatory, antibody-mediated, & cell- mediated responses (nonspecific Responses).They are important not only for phagocytosis, but also for antigen presentation.

b). Lymphocytes- These are not all of the lymphocytes, but some of the important ones. These include:

📌 B cells - They produce Antibodies (Ab), i.e. Y-shaped protein molecules which bind to specific targets (antigens) and tag them for destruction by phagocytes or the complement system.

📌Cytotoxic T cells - These are involved in the cell-mediated response- they directly destroy body cells already infected by certain viruses or parasitic fungi.

📌Helper T cells - These are involved in the antibody-mediated and cell-mediated responses- they stimulate the rapid division of B cells and cytotoxic T cells by producing compounds called interleukins.

📌Memory cells -These are certain B cell & T cells which are produced during a first encounter with a specific invader (primary immune response), but are not directly involved in this first attack. They circulate freely and respond rapidly to any subsequent attacks (secondary immune response) by the same type of invader. Doing your part to help your body to fight diseases makes your body very happy and healthy

The following are ways of boosting our body's immunity:

▪️ Eating more of whole plant foods which are usually rich in antioxidants.

▪️ Eating more food with probiotics, which help to flourish the gut flora.

▪️ Reduce intake of added sugars in food/ drinks.

▪️ Do regular moderate exercises which help the immune cells to regenerate.

▪️ Always hydrate- best fluid is water.

▪️ Manage stressful situations by exercise, Journaling, sharing and meditation/prayer.

▪️ Eat more healthy fats eg olive oil, avocado, chia seeds etc.

▪️ Get enough sleep daily.

▪️ Get enough sunshine.

▪️ Avoid use of many antibiotics, especially broad-spectrum.

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