SAQ Flashcards
Your friend at SCU asks you why, despite exercising, eating calcium-rich foods, and taking vitamin D supplements, they never get taller. Your friend had a little growth spurt in high school but has not become taller since then. Please explain to your friend what happened to their bones before puberty, and why the situation is different now. Use and embolden the following 8 terms in your response.
Chondrocyte
Osteoblast
Estrogen
Collagen
Epiphysis
Calcium Phosphate
Hyaline
Mitosis
Despite exercising, eating calcium-rich foods, and taking vitamin D supplements, my friend will not get taller because growth hormones more present during puberty not only help drive bone growth but also end it. One way our bones grow is through endochondral ossification. During this, chondrocytes make a hyaline cartilage model of the bone, and then osteoblasts come in and build bone tissue in place of it. Another way our bones grow through epiphyseal growth is in the epiphysis of long bones, chondrocytes rapidly divide by mitosis, pushing new chondrocytes away from them, stacking, and lengthening our bones as a result which is how we get taller. Bones are mostly made of collagen which provides bones resistance against fracture. Calcium phosphate is a mineral in the bones that adds strength and hardens the framework made by osteoblasts. Hormones that are present in higher quantities during puberty in both males and females stimulate more cell division and activity in both chondrocytes and osteoblasts. However, estrogen-only stimulates osteoblasts while shortening the lifespan of chondrocytes. So estrogen, which is released in higher amounts during puberty, eventually leads to all the chondrocytes dying off. After they die off, the osteoblasts replace any remaining cartilage with bone and the growth of your bones and height is over.
Humans would be so much better off if all inflammation was cured with a medicine!
Inflammation is an important human response necessary to help your body function. For example, when your immune system is fighting a pathogen, one of the first steps in fighting it is the macrophages trying to engulf the pathogen. In doing this, the macrophages call in for backup, opening blood vessels and resulting in inflammation. It is this inflammation and increased blood flow that allows nutrients, immune cells, and antibodies to get to an infected area much faster and help your immune system fight off invading pathogens more quickly and efficiently. So overall, humans would not be better off if all inflammation was cured with medicine.
The lungs work by stretching themselves in and out like a muscle
To inhale, the diaphragm and other muscles contract which increases the volume of the lungs, reducing the pressure and creating a vacuum suction. To exhale, the diaphragm and other muscles relax, decreasing the volume and forcing the air out. The lungs work like a plunger or a syringe by contracting and relaxing instead of just stretching themselves in and out.
Drugs of abuse stimulate dopamine signaling but do not change the brain
Drugs of abuse do stimulate dopamine signaling, however, they do change the brain after drug use. Dopamine overstimulation results in the brain shutting some dopamine receptors down permanently. The result of this is because there are fewer receptors available, a person needs to use more of the drug in order to feel high or even just normal. After they stop using the drug, they will have fewer dopamine receptors, resulting in feelings of depressions and sickness when they withdraw drug usage. So although part of this statement is correct, drugs of abuse do change the brain.
Your acquaintance John loves to solve puzzles and brain teasers. He is happy being a quick thinker but does not understand how brain cells can communicate with each other to make thinking possible. He knows you studied the subject in Biol 2 and asks you for an explanation. Please explain to John how nerve cells send a signal from one neuron to another. Use and embolden the following 8 terms in your response.
“Action Potential” “Neurotransmitter” “Voltage-gated” “Resting Potential”
“Sodium” “Axon” “Potassium” “Saltatory Conduction”
Nerve cells send a signal from one neuron to another by an action potential. When a neuron is in its resting state l, the inside of the neuron has a negative charge. The resting potential tells us what happens when a neuron is at rest and is the difference between the voltage on the inside and outside of the cell. The neuron’s cell membrane is voltage-gated meaning it has ion channel proteins that are activated by changes in the electrical charge and they open and close to let certain ions into balance these charges or create an electrical current. When the brain wants to send a signal, it stimulates the neuron and causes an explosion of electrical activity, Sodium rushes into the neuron and potassium rushes out creating a depolarizing current. When an action potential arrives at the axon terminal, neurotransmitters are released into the synaptic cleft and bind to receptors on the receiving cell may lead to action potentials in that cell.
What are three variables controlled by homeostasis in your body?
What is one thing you learned in Biol 2 that will someday help you make a decision in your daily life? What decision?
One thing I learned in Biol 2 that will someday help me make a decision in my daily life is how drugs can affect the brain. When you use drugs for a prolonged amount of time, the brain shuts down dopamine receptors so when you stop using the drug you feel depressed and possibly sick due to less dopamine being released. I will remember this when if I am ever offered any type of drug and will say no because I want to prevent this from happening and becoming addicted to drugs.
