Bio215 Unit 5 - Human Physiology (33-37)

Nervous system, circulatory and respiratory system, muscle system, reproductive system

What are the different scope levels of an organism?

Cells, tissues, organs, organ systems, and organism

What is homeostasis?

A dynamic state of equilibrium where internal conditions can vary but within narrow limits (thermoregulation, osmoregulation, blood glucose, etc)

What is a positive feedback loop?

A stimulus/variable affects the homeostatic state, a sensor notices the deviation and tells the control center, the control center tells the effector to intensify the response to the variable

What is a negative feedback loop?

A stimulus/variable affects the homeostatic state, a sensor notices the deviation and tells the control center, the control center tells the effector to neutralize/counter the response to the variable, ie bringing something back to normal

How is homeostasis affected for Type I vs Type II diabetes?

Type I: Immune system attacks pancreas and body cannot produce insulin

Type II: Insulin receptors are damaged and cells can’t use insulin to take sugar out of blood

In what order does blood flow through the heart?

DEOXYGENATED - vena cava - Right Atrium - tricuspid valve - Right Ventricle - pulmonary/semilunar valve - pulmonary artery - lungs (OXYGENATED) - pulmonary vein - Left Atrium - bicuspid/mitral valve - Left Ventricle - aortic semilunar valve - aorta - body

What differentiates arteries from veins?

Arteries go Away from the heart, veins go towards it

Why are the pulmonary vein and artery unique?

Even though they follow the artery/away and vein/towards rule, they don’t follow the arteries/oxygenated and veins/deoxygenated rule!

Which side of the heart has a thicker wall?

The left ventricle/atrium has a thicker wall than the right, because the arteries (systemic circuit, away from the body) must be stronger.

What does the pulmonary circuit do?

Transports blood between the heart and the lungs

What does the systemic circuit do?

Transports blood between the heart and the body

What is the function of heart valves?

Pressure and flow control

What arteries supply the heart muscle with oxygen and nutrients?

coronary arteries

What happens if the coronary arteries become blocked?

A heart attack

What are the three layers of a blood vessel?

Connective tissue, then smooth muscle inside, then the epithelium

How do capillaries work?

They are the smallest blood vessels, with an epithelium only one cell thick so that gas exchange (O2 for CO2) and nutrient exchange can occur. They make a “web” between arteries and veins.

What does EPO (erythropoietin) do?

Stimulates RBC production in the bone marrow

What is the main difference in structure between arteries and veins?

Arteries have thick muscles, veins have thin muscles and valves

What do RBCs not have?

A nucleus

What kind of macromolecule is hemoglobin?

a protein

What molecule does hemoglobin transport?

Oxygen

What is capillary filtration?

Alvioli in the lungs are covered in capillaries and conduct gas exchange (CO2 to O2).

What is the difference between the Central Nervous System and the Peripheral Nervous System?

The CNS is the brain and spine, the PNS is all other branching nerves

What is the difference between the sympathetic and the parasympathetic nervous system?

Sympathetic is flight/fight/freeze and is active and intentional. The PS is rest/digest and happens largely subconsciously

What is the flow of information through your nervous system?

Information is received through sensory neurons and carried to the brain. The brain processes the information and uses motor neurons to tell muscles/organs what to do.

What are the 5 types of sensory receptors?

Thermo (heat), mechano (pressure/movement/texture), chemo (smell/taste), photo (visual), and noci (pain)

What is the flow of action through a neuron?

Dendrites carry impulses to cell body, then the axon carries the signal away from the cell body. The axon/synaptic terminal is at the end of the axon and send impulses to dendrites on receiving cells.

What is the myelin sheath?

It is a layer on the outside of axons which insulates them and speeds up electrical impulses while preventing “crossed wires”

How is an action potential transmitted across neurons?

1. Action potential/impulse reaches axon terminal

2. Calcium ions enter terminal and stimulate synaptic vesicles that have neurotransmitters, which fuse with the presynaptic neuron membrane

3. Neurotransmitters are released and diffuse across the synapse

4. Neurotransmitters bind with receptors on postsynaptic neuron

5. The neuron is inhibited or excited, or a muscle contracts. The neurotransmitter is broken down or returned to the sending neuron

What does acetylcholine do?

It is a neurotransmitter that controls muscle contraction, and also affects learning and memory

What are the three ways that chemicals such as nerve agents or toxins can affect your nervous system?

They can either promote what a normal neurotransmitter does, interfere with (decrease) the effect of a normal neurotransmitter, or replace (mimic) a normal neurotransmitter

How do tendons and ligaments differ?

Tendons connect muscles to bones, ligaments connect bones to bones at joints.

What do cartilage, yellow bone marrow, and red bone marrow do?

Cartilage cushions joints, YBM stores fat, RBM makes red and white blood cells

What do osteoarthritis, rheumatoid arthritis, and osteoporosis do?

Osteoarthritis degenerates the tissue between joints, rheumatoid arthritis is an immune disorder that targets joints, and osteoporosis is a genetic disorder that weakens bones (affected by estrogen, calcium, and amount of muscle)

What is the anatomy of a muscle fiber?

Myosin (thick) filament is attached to each end of an actin (thin) filament. The sarcoplasmic reticulum is on either outside end of the myosin filament, and the sarcomere is the middle. This unit makes up a microfibril, and many microfibrils make one muscle fiber (which is one muscle cell).

How does the sliding filament model work?

1. Acetylcholine binds to AC receptors

2. Calcium is released from the sarcoplasmic reticulum and binds to actin, which exposes the myosin-bonding sites on the actin

3. The myosin head binds to the actin, performs the “power stroke” which makes the myosin filament overlap with the actin filament, contracting the muscle

4. ATP binds to the myosin head, allowing it to release and the muscle to relax

What is the process of meiosis?

Process to go from diploid parent cells to haploid daughter cells

What are the steps in the process of meiosis?

Chromosomes are duplicated, create sister chromatids, and “cross over” in the parent cell - essentially, a sister chromatid (one X) finds another sister chromatid and swaps a bit of DNA with it. Then, during independent assortment, chromatids line up in pairs (making two lines). In meiosis 1, one “line” of chromatids is pulled to each side and the parent cell splits. In meiosis 2, each sister chromatid separates (forming two lines again) and each “line” is pulled to one side and the cell splits again, making a haploid cell with ½ the DNA of the original.

What the two examples of haploid cells?

Eggs and sperm

What is non-disjunction and what happens in it?

Chromatids fail to split at either independent assortment of meiosis 2. If at IA, both paired sister chromatids go to one cell and neither to the other, leading to a 50-50 chance of trisomy or monosomy. If at M2, the sister chromatid goes to one cell and the other cell has nothing, leading to a 50-25-25 chance of normal offspring, trisomy, or monosomy.

What is the anatomy of a sperm?

The head has the DNA, the acrosome is around the head and stores enzymes to penetrate the egg’s jelly coat, the “middle” has mitochondria, and the tail moves.

What is the path that sperm takes through the penile structure?

Sperm is created in the testes (which are in the scrotum), stored in the epididymus (which is attached to the testes), travels through the vas deferens to the seminal vesicles where semen is added, is stored again in the prostate, then is ejected through the urethra in the penis

How does the birth control pill affect the pregnancy feedback loop?

Progesterone tells your body to stop making luteinizing hormone (LH), thereby stopping ovulation. Progestin stops egg release and thickens cervical mucus. Estrogen lowers FSH and LH, further stopping ovulation and reducing the uterine lining.

What is the % effectivity of vasectomy/tubal ligation, male condoms, and hormonal methods (such as the pill)?

99%, 82%, and 91% respectively

How can you differentiate the trachea from the esophagus?

The trachea has cartilage rings

Why would a rat’s liver be very large?

Helps them digest lots of toxins from their diet, produces bile which is important because they have no gallbladder to store it in.

What are some biology concepts from this year that relate to your future work as an AF officer?

Understanding digestion and nutrition - important to stay in physical health

Understanding reproduction and contraception - important for Airmen to know how to prevent pregnancy, which can affect the mission

Understanding the environment and global warming - making climate informed decisions is a goal of the DoD to protect our assets and prevent political instability

Understanding how diseases/viruses spread - important for service members to understand immunity to avoid getting sick, which can affect the mission. Especially important in foreign areas with diseases that we may not already be immune to

Understanding the nervous system - in active warzones, physical or CBRN threats can affect the nervous system in numerous ways, so understanding it is crucial to a rapid response

Understanding the human body - we may not have biologists in the AF, but we do have doctors, and basic biology is an obvious precursor to this career field and other medical careers

Understanding microbiology - biological weapons are increasingly becoming a threat, so developing biodefense strategies is a growing career field in the military overall