Biology Instructor Receives Teaching Award

 

Biology Instructor Receives Teaching Award

 

Biology instructor Jeff Schinske was recently selected as the 2018 recipient of the Outstanding Undergraduate Science Teaching Award (OUSTA) from the Society for College Science Teaching. Schinske is the first community college instructor to receive this prestigious award. 

The OUSTA recognizes the achievements of science teachers who have enhanced the profession through excellence, scholarship and service. Schinske will accept the award and present at the National Science Teachers Association conference in March. 

In his current position, Schinske co-coordinates Foothill's anatomy and physiology courses and serves as the lead biology curriculum reviewer for California's statewide articulation system, C-ID. His current research focuses on equity and inclusion in science classrooms, the underrepresentation of community colleges in biology education research, and STEM faculty development. 

Schinske has published numerous peer-reviewed articles on STEM teaching and learning, has served as PI or Co-PI on four NSF grants, was interviewed by Nature for an article on community college teaching, and recently appeared as a senior author on an article in the Proceedings of the National Academy of Sciences (PNAS) on measuring faculty teaching practices in STEM classes. He is frequently invited as a plenary speaker on issues of equity and diversity in STEM education and has facilitated discussions on the topic at institutions ranging from small community colleges to large universities. 

 

https://www.lifescied.org/doi/10.1187/cbe.16-01-0002 

 

Langerhans cells

 
Langerhans Cell
Kate Latham
By:
Kate Latham
Biologydictionary.net Editors. (2021, April 26). Langerhans Cell. Retrieved from https://biologydictionary.net/langerhans-cell/
Reviewed by: BD Editors
Last Updated: April 26, 2021

Langerhans cells are a type of immune cell found primarily in the epidermis that have important roles in the stimulation and suppression of the adaptive immune response. They are members of the dendritic cell family and function as antigen-presenting cells. When a Langerhans cell encounters a pathogen, it engulfs the infectious agent and breaks it down into protein fragments. Some of these fragments are displayed on the surface of the cell and presented to naïve T cells in the lymph nodes to stimulate an immune response.

 What is a Langerhans Cell?

Langerhans cells are a type of immune cell found in the skin (AKA the epidermis). Like all immune cells, Langerhans cells are formed in the bone marrow. Once released from the bone marrow, they circulate in the blood before migrating to the skin, where they guard the epidermis against infection from pathogens.

Langerhans cells are members of the dendritic cell family and function as antigen-presenting cells (APCs) in the skin. They capture any pathogens they find roaming the epidermis and display their antigens on their surface to stimulate other immune cells into action.
Where Are Langerhans Cells Found?

Langerhans cells are present in all layers of the epidermis and the respiratory, digestive, and urogenital tracts. When they encounter a pathogen, Langerhans cells migrate to the lymph nodes to present their antigens to naïve T cells and activate the adaptive immune response.

 Function of Langerhans Cells

Langerhans cells are members of the dendritic cell family. Their main role is to alert other components of the adaptive immune system to the presence of pathogens and other infectious agents on the skin.
Langerhans Cells as Antigen-Presenting Cells (APCs)

Langerhans cells are phagocytic cells, meaning they engulf other cells or particles. They are also antigen-presenting cells (APCs), and can display fragments of engulfed pathogens on their cell surface to stimulate an adaptive immune response.

When a Langerhans cell encounters a harmful pathogen in the skin, it ingests it and breaks it down into protein fragments. Some of these fragments are displayed on the surface of the Langerhans cells as part of the Major Histocompatibility Complex (MHC).

Next, the Langerhans cells migrate to the lymph nodes to present their antigens to naïve T cells. This activates the T cells to launch an immune response and stimulates them to find and destroy the invading pathogen.
Langerhans cells present antigens to naive T cells
Langerhans cells are antigen-presenting cells
Immune Suppression by Langerhans Cells

Langerhans cells play a role in stimulating the adaptive immune response against pathogens, but they are also known to suppress immune function. The skin is naturally populated by ‘friendly’ bacteria which, although ‘foreign’ to the body, are not known to cause disease. In the presence of non-pathogenic bacteria, the Langerhans cells coordinate immune tolerance, i.e., they prevent the immune system from responding. This prevents unnecessary and potentially harmful activation of the immune system.
Langerhans Cells Prevent Autoimmunity

Langerhans cells help to prevent autoimmunity (an immune response against healthy cells) by promoting immune tolerance.

Under ‘non-dangerous’ conditions (i.e., when there are no pathogenic agents present), Langerhans cells promote the activation and proliferation of T regulatory (Treg) cells in the skin. Treg cells secrete cytokines that promote immune tolerance and, in doing so, prevent unnecessary and potentially harmful immune activation.

In the presence of a pathogen, however, Langerhans cells promote the activation of effector T cells and limit the activation of Treg cells. They stimulate the effector cells (namely, helper and cytotoxic T cells) to launch an immune response against the foreign invader and clear infections from the skin.
Langerhans cells may stimulate either Treg or effector T cells
Langerhans cells stimulate Treg cells to promote immune tolerance
What is Langerhans Cell Histiocytosis (LCH)?

Langerhans Cell Histiocytosis (LHC) is a rare type of cancer in which abnormal Langerhans cells grow and multiply rapidly. This leads to a build-up of Langerhans cells in various regions of the body, including the skin, mouth, lymph nodes, thymus, eyes, endocrine system, central nervous system (CNS), liver, spleen, lungs, or bone marrow. The abnormal proliferation of Langerhans cells can cause tissue damage and lesions to form in affected body parts, and symptoms vary depending on which region of the body is affected.

In approximately 80% of cases, LCH affects the bones (typically the skull or the bones of the arms or legs). This causes pain and swelling and may lead to bone fracture. LHC is also known to frequently affect the skin, where it may cause rashes, bumps, and blisters that can be mild or severe. If the pituitary gland is affected, LHC may disrupt hormone production, which may lead to infertility or, in adolescents and children, delayed or absent puberty. LHC may also affect the thyroid, leading to the disruption of the patient’s normal skin and hair texture, body temperature, and behavior.

Melanocytes

 

Lamellated corpuscle

 The lamellar corpuscle is a type of large, ovoid, rapidly adapting, encapsulated nerve ending sensitive to pressure, touch, and vibration. The most complicated of the nerve endings, its core contains the nonmyelinated nerve terminal and its Schwann cells, surrounded by concentric layers of modified fibroblasts, in cross-section resembling a sliced onion. It is found in the skin and deeper tissues, particularly in the palms, soles, digits of hands and feet, joints, external genitalia, and breasts (Dorland, 2011).

application 8 revised

     I would explained my friend that during weight lifting,her muscles primarily produce energy (in the form of ATP) through aerobic respiration, which involves using oxygen to break down glucose and fuel muscle contractions.When her muscles contract, ATP molecules had to broken down to release energy.The frequency and intensity of these signals determine the force and duration of muscle contractions.

(1)  For short bursts of intense activity like weight lifting , her muscles rely on stored creatine phosphate (CP) to rapidly regenerate ATP.

(2)  For moderate-intensity exercise, glucose breakdown via glycolysis generates ATP. 

(3) For longer activity oxygen is used to break down glucose into ATP molecules, providing sustained energy

            When lifting weights, the nervous system coordinates the firing of motor neurons, which stimulate muscle fibers to contract.Initially, muscle contractions are often partial and not strong enough to fully shorten the muscle cell.To achieve full muscle cell shortening and sustained contraction, the muscle cell must receive multiple signals in succession from the neuron.

       During workouts, the interaction between actin and myosin generates force in the muscle. Increasing the amount of actin and myosin results in greater force production and thicker, more defined muscles when lifting heavier weights.

         Consistent work out perform training, muscle fibers increase in size due to increased protein synthesis and the addition of contractile proteins actin and myosin. Aerobic exercise promotes mitochondrial growth within muscle cells. More mitochondria mean better ATP production through aerobic respiration.

     

 

 

 1.During her weightlifting workout, her muscles generate energy (ATP) primarily through a process called aerobic respiration, where oxygen is used to break down glucose into ATP molecules, providing the necessary energy for muscle contraction. Additionally, muscles could use stored energy in the form of creatine phosphate (CP). Another way that uses energy stored within carbohydrates from the blood or from muscle cell reserves to generate ATP.

2.During her workout, her nervous system sends signals to her muscle cells through neurons, triggering action potentials that result in muscle contraction. The frequency and intensity of these signals are adjusted by her nervous system to match the demands of the exercise.

However, this contraction isn't usually strong enough to fully shorten the muscle cell and it's more like a partial contraction.

To fully shorten the muscle cell and keep it contracted, it needs to receive multiple signals, one after the other, from the neuron. The more signals it gets in a row, the more the muscle cell shortens, and the longer it stays contracted.

When she workout, the pulling of actin by myosin provides force in her muscle, therefore adding more actin and myosin will get more force. That will also make your muscles thicker and appear more muscle when she continues lifting heavier weights.