NEUR 1202 Lecture Notes - Lecture 6: Upper Respiratory Tract Infection, Thymus, White Blood Cell
Lecture 6
Lecture 6
Health & Immunity
Blood Brain Barrier:
- The brain is surrounded by a network of blood vessels
- Be thought of as a security system that allows only the entry of essential nutrients while
blocking the other substances
- Made of endotheitial cells that surround the blood vessels
- Endothelial cells are tightly wedged together which makes a nearly impermeable boundry
between the brain and bloodstream
- Very small or fat soluble compounds can slip through the endothelia cells and make up
the BBB without much effort
- Security system that keeps stuff out
- Larger molecules must be ferried across by specialized proteins known as transporter
proteins
Health and Immunity:
- Strong relationship between the immune system and the central nervous system
- Factors involved in the immune response can significantly impact our mental health
- The stress response can affect every system in the body, including the brain itself
- The connection between and the immune system which is relevant for stress and mental
illness
Psychoneuroimmunology
Bi-directional Communication
- The brain can talk to the immune system, affecting its ability to protect us
- The immune system can also talk to the brain, affecting how we think and feel
What is the Immune System?
- Our human body is the perfect climate for all microorganisms
- The Immune System is responsible for protecting your body from these microorganisms
- Cells of the immune system constantly monitor the internal environment for signs of
invasion by bacteria or viruses, as well as evidence of tissue damage
- The immune system is extremely powerful, and is highly regulated in order to maintain
the optimal levels of function
How does the Immune System work?
- It is decentralized which means that it exists outside the CNS and our BBB makes our
brain largely protected from the immune systems in the body
- It has cells known as immune cells that circulate throughout the blood stream and act
directly where they are needed
- The spleen, lymph nodes, thymus and bone marrow acts as factories and repositories for
immune cells
- The nervous system, endocrine system, and immune system relies chemical
communications to organize its functions
- Immune cells talk to other immune cells through chemical signals
- The immune system has two basic divisions
1) Innate Immune System- first line of defense; activates immediately when your body
detects a foreign invader or threat
- How do they recognize foreign invaders? – All the bacteria have molecules that are
present on them that cells of the innate immune system have receptors for
- Macrophages have receptors that recognize the molecules on foreign invaders and can
bind to them and eat them (phagocytosis)
- It is also body’s early warning system, alerts the other arms of the immune system of the
threat
- Messages are passed between immune cells using chemicals called cytokines
- Cells of the innate immune system such as macrophages release cytokines into circulation
2) Adaptive Immune System – activated by cytokines and involves two systems of
leukocytes (white blood cells)
- Cell mediated immunity involves T cells named because they develop in the thymus
- T cells are activated by cytokine signals sent by cells and the T cells develop into a form
that attacks body cells which have been infected and kill it
- Antibody Mediated Immunity involves B cells which produce antibodies that bind to
antigens on pathogens to kill or deactivate them
- if specific viruses enter your body the B cells will notice and instruct your body to kill it
- The immune response is coordinated effort between all three systems that typically
follows the same progression
Cytokines:
- Trigger an inflammatory response (redness, swelling, fever, body temperatures raise,
aches, etc)
- Help body to destroy abnormal cells
- Attract more innate immune cells
- Activate the adaptive immune system
- They are molecules that coordinate the immune response, and tell the body that is under
attack
- Cytokines transmit signal to our brain to make us feel sick and produce sickness behavior
that brain is responsible for
- Cytokines are the “sickness hormones” and sends signals to the brain
- Receptors on blood vessels in the brain detect circulating IL – 1 or pathogens and
stimulate cytokine production in the brain
- Circulating IL – 1 can be actively transported to the brain
Cytokines and Depression:
- Sick people act similarily to depressed people
1. Individuals with depression have higher level of cytokines
2. Giving people cytokine treatments can produce depressive symptoms
3. Depression is more common among people suffering from inflammatory diseases
Stress and Immune System:
- HPA axis can also affect the immune system
- This fits into our view that the stress response is designed to help the body deal with short
term challenges
- Problems arise when the HPA axis is over and under activated
- Cortisol is immunosuppressive
- The cortisol anti inflammatory action makes it a common drug for treating autoimmune
disorders
- Stress suppresses the immune system
- Short term effect of a mild stressor to augment immunity
- During the SAM activation of the stress response, the immune cells like leukocytes
mobilize to the skin, lymph nodes, and other battle stations where they can easily be
recruited if an infection/ invasion were to happen
- Treatment with the NEP and EP can mimic the immune enhancing effect of acute mild
stress providing further validation
- Chronic social stress increases susceptibility to have a common cold
- Odds of getting sick were related to how much stress the person had experienced during
that year
- Exam periods at university are stressors that seem to produce increased rates of upper
respiratory tract infection
- Lecture 6
Health & Immunity
Blood Brain Barrier:
- The brain is surrounded by a network of blood vessels
- Be thought of as a security system that allows only the entry of essential nutrients while
blocking the other substances
- Made of endotheitial cells that surround the blood vessels
- Endothelial cells are tightly wedged together which makes a nearly impermeable boundry
between the brain and bloodstream
- Very small or fat soluble compounds can slip through the endothelia cells and make up
the BBB without much effort
- Security system that keeps stuff out
- Larger molecules must be ferried across by specialized proteins known as transporter
proteins
Health and Immunity:
- Strong relationship between the immune system and the central nervous system
- Factors involved in the immune response can significantly impact our mental health
- The stress response can affect every system in the body, including the brain itself
- The connection between and the immune system which is relevant for stress and mental
illness
Psychoneuroimmunology
Bi-directional Communication
- The brain can talk to the immune system, affecting its ability to protect us
- The immune system can also talk to the brain, affecting how we think and feel
Document Summary
Exam periods at university are stressors that seem to produce increased rates of upper respiratory tract infection. The brain is surrounded by a network of blood vessels. Be thought of as a security system that allows only the entry of essential nutrients while blocking the other substances. Made of endotheitial cells that surround the blood vessels. Endothelial cells are tightly wedged together which makes a nearly impermeable boundry between the brain and bloodstream. Very small or fat soluble compounds can slip through the endothelia cells and make up the bbb without much effort. Larger molecules must be ferried across by specialized proteins known as transporter proteins. Strong relationship between the immune system and the central nervous system. Factors involved in the immune response can significantly impact our mental health. The stress response can affect every system in the body, including the brain itself. The connection between and the immune system which is relevant for stress and mental illness.
