Goodwin Exam 1

- review questions and quizzes

Are cells at equilibrium? Then what are they when everything is balanced?

• No

  • body is in osmotic equilibrium, but chemical and electrical disequilibrium

• homeostasis: maintaining dynamic steady states

What are the components of homeostatic control mechanisms?

input signal → controller → output signal

Where is the most volume of the water in the human body?

• intercellular fluid

What kind of IV fluid would you give someone who was dehydrated? Why?

• Half-normal saline (hypotonic)

• there will be more salt in the cells than in the solution, meaning that the water will enter the cells and aid rehydration

What ions are most responsible for creating the resting membrane potential of cells?

• Na, Cl, K, Ca

What is the resting potential of a cell?

• -70 mV

How does the extracellular fluid affect the intercellular fluid?

• extracellular fluid regulates the intercellular fluid

What molecules can move freely through the phospholipid bilayer?

• small, non-polar molecules

How are other molecules moved in and out of the cell?

• channel proteins, ion pumps, carrier proteins, etc

What is the difference between membrane channels and carrier proteins?

• membrane channels (bridges)

  • do not require energy input

• carrier proteins (elevators)

  • require an energy input

What is the difference between passive and active transport?

• passive- no energy input

• active- requires an energy input

How do organs and organ systems maintain homeostasis?

• cell communication

How are signals communicated from one cell to another?

• autocrine, paracrine, endocrine signaling

What is the most common stain used by pathologists to diagnose disease?

• H & E

What is the method that allows you to investigate specific proteins in tissues?

• immunohistochemical staining

What imaging technique allows for the resolution of cell organelles?

Transmission Electron microscopy

What type of cell junction is capable of excluding water?

• tight junction (occluding junctions, zonula occludens)

What type of cell junction is the strongest?

• desmosome

What causes pemphigus vulgaris?

• autoimmune antibodies attach to desmosomes within the epidermis of the skin

• keratinocytes disconnect from one another, causing blistering

What type of cell junction connects the cytoplasm of two cells?

• gap junction

Compare and contrast the three classes of hormones.

• steroid

  • cholesterol-derived, lipophilic, bound to transport proteins, able to diffuse through cell membrane

  • estrogen

• peptide

  • water soluble, zymogens that are modified post-transcriptionally, short half-life

  • insulin

• amines

  • derived from tryptophan or tyrosine

    • melatonin, catecholamines, thyroid hormones

What are the two parts of the pituitary gland?

• adenohypophysis (anterior pituitary)

• neurohypophysis (posterior pituitary)

What kinds of hormones are secreted by the anterior pituitary (adenohypophysis)?

• trophic hormones (small proteins or glycoproteins)

What is a “herring body” and where is it found?

• axonal dilatation that accumulates vesicles containing hormones

• found in posterior pituitary

What hormones do the posterior pituitary (neurohypophysis/pars nervosa) secrete?

• Oxytocin

• ADH

How would a pituitary tumor affect vision?

• tumor presses on the optic chiasma, causing blindness or vision disturbances

How do the neurohypophysis and adenohypophysis work together to regulate thyroid hormone release?

• anterior pituitary produces six trophic hormones

• posterior pituitary stores hormones, but also produces ADH and oxytocin)

• modulated by positive and negative feedback, controlled by levels of circulating hormone

What structure and which molecule induces the ectoderm to become neural ectoderm?

• notochord

• Sonic Hedgehog (SHH)

A mother brings in her 1y/o and says that the frequency of BMs has gradually decreased. The child has a swollen belly and is in pain, Imaging shows an enlarged section of the colon. Diagnosis? What is the cellular mechanism?

• Hirschprung’s Disease

• Neural Crest Cells

A pregnant female has been diagnosed with megaloblastic anemia. What is the concern and what should be prescribed?

• neural tube defects

• folate

An ultrasound of an 18-week-old fetus reveals a neural tube defect. What is the prognosis?

• depends on the NTD

  • some are fatal (anencephaly), while others may be fixed depending on severity (cleft palate, spina bifida, etc)

Name at least four parts to a neuron

1. dendrites

2. soma

3. hillock

4. axon

5. synaptic cleft

What kinds of neurons exist?

• bipolar, multipolar, pseudounipolar, unipolar

What myelinates axons in the CNS?

• oligodendrocytes

What type of neuron is the fastest?

• large myelinated neurons

What cell type in the CNS is derived from mesoderm and what is the function?

• microglia, macrophage of the CNS

What is the function of an astrocyte?

• supports neurons

What myelinates neurons in the PNS?

• schwann cells

Why can’t the CNS regenerate very well?

• astrocytes prevent regeneration

Obeying Ohm’s law, if the current increases through a membrane, what happens to membrane resistance?

V=IR

• decreases

What are the three ways that an ion channel can be stimulated to open?

• voltage gated, chemically gated, mechanically gated

If stimulated in the middle of an axon, which way will the depolarization travel? Anterograde or retrograde?

• both

What is the difference between graded potentials and action potentials?

• graded potentials come in through dendrites, can fade out

• action potentials travel from hillock down axon, all or nothing

What is the difference between spatial and temporal summation?

• spatial- location based

  • closer to axon hillock will increase chances of firing

• temporal- time based

  • many in a short time period

At what point will an action potential be generated?

• -50 mV

When Na+ ions enter the cell, do they depolarize it or hyperpolarize it? What about Cl- entering the cell? What about K+ exiting the cell?

• Na+ depolarize

• Cl- & K+ hyperpolarize

What is the difference between the absolute refractory period and the relative refractory period?

• absolute: no AP will fire

• relative: AP may fire, but will not be as strong

Describe the roles of the Na+, K+ voltage gated ion channels and the Na+/K+ pump during an action potential.

• Na+ channels open at -50 mV, causes Na+ to flood into the cell, cell depolarizes

• Na+/K+ pump brings K+ back into the cell, repolarizing the cell

Do ions entering and exiting the cell affect the concentration gradients of the ions in the ECF and ICF?

• not really

How does saltatory conduction differ from other forms of conduction?

• conduction jumps between nodes of ranvier

Where are the Na+ and K+ voltage gated ion channels in myelinated axons?

• nodes of ranvier

What are the two types of synapses?

• electrical and chemical

What is the difference between the ion channels at the synapse versus the rest of the axons?

• synapse takes in Ca+ instead of Na+

What protein complex is needed to fuse synaptic vesicles with the cell membrane allowing for the release of neurotransmitters? What simulates this process? What inhibits this complex?

• SNARE

• Ca+ stimulates

• neurotoxins inhibit

How can one neurotransmitter have two different affects?

• different receptors

What gets recycled in the synapse?

• neurotransmitters, receptors

What intercellular filament transports synaptic vesicles to and from the synapse?

• microtubules

What motor protein moves cargo anterograde? Retrograde?

• Anterograde: kinesin

• retrograde: dynein

What is long-term potentiation and how does it affect learning?

• build-up of receptors at the synapse

• how learning occurs

What is the only cell in the CNS that is not derived from neural ectoderm?

• microglia

When are the gyri and sulci of the brain formed?

• after birth

What are chiari malformations?

• parts of the brain trapped in the magnum foramen

Where do sensory nerves enter the spinal cord?

• dorsal side

Where do motor neurons leave the spinal cord?

• ventral side

What are the three layers of the meninges?

• Dura mater

• arachnoid layer

• pia mater

Why is the somatic nervous system called a one neuron system?

• uses single, often long, neurons for sensory and motor

What are the two components of the autonomic nervous system?

• sympathetic and parasympathetic

how is the spinal cord organized?

• grey matter on the inside, white matter on the outside

  • opposite of the brain

How is the BBB different between the choroid plexus and the rest of the brain?

• fenestrations

What are the four lobes of the brain and their functions?

• Frontal- decision making, personality

• parietal- sensory

• temporal- hearing

• occipital- visual

What is the function of the cerebellum?

• motor coordination

What is the function of the limbic system?

• emotion, memory

What is the function of the Broca’s and Wernicke’s area and how are they related to other areas of the cerebrum?

• broca- language production

• wernicke- language comprehension

What happens if the broca’s and wernicke’s areas are damaged?

• Broca- won’t be able to form language

• Wernicke- won’t be able to comprehend language

What is decussation and where does it occur?

• crossing over- occurs in the medulla- spinal cord juncture

How is sensory input related to voluntary movement?

• sensory input guides voluntary movement

What cell type produces most of the ECM in connective tissues?

fibroblasts

Which CT cell type can phagocytize cellular debris, secrete cytokines, and present antigens that help mediate the immune system?

• macrophages

Which CT cell type mediates hypersensitive reactions like allergies?

• mast cells

What is the difference between collagen fibers, reticular fibers, and elastic fibers of the ECM?

Which fiber type can bear the highest amount of tension?

collagen

Ascorbic acid is a cofactor for the production of what kind of protein fiber?

collagen

What is ground substance in CT and what are its functions?

What kind of collagen is found in all cartilage?

Compare and contrast hyaline, elastic, and fibrocartilage.

Compare and contrast chondroblasts and chondrocytes.

What is the function of the perichondrium and why is articular cartilage prone to osteoarthritis?

• articular cartilage does not have perichondrium

What kind of cartilage is articular cartilage?

• hyaline cartilage

What kind of cartilage is found in the load-bearing intervertebral discs?

fibrocartilage

Intercellular fluid is in what type of equilibrium?

• osmotic equilibrium with the extracellular fluid

If living cells are placed in a hypotonic solution, will water go into the cell or out of the cell?

• out of the cell

What are the two most important ions in maintaining the resting potential of a eukaryotic cell?

• sodium and potassium

Where is the potassium concentration highest?

• intercellular fluid

Compare and contrast facilitated diffusion and active transport.

• facilitated: diffusion moves down a concentration gradient, does not require an energy input

• active: requires an energy input to cross the membrane

A patient was infected with an attaching/effacing bacteria which disrupts tight junctions of intestinal cells. What function has this tissue lost?

• no longer able to function as a barrier/seal

What is the most common stain used by pathologists to diagnose diseases?

H&E

Where are the receptors for steroid hormones usually found?

• In the cytoplasm

What forms the pituitary gland?

• part of the brain and part of the oral epithelium

Name a hormone that is released by the anterior pituitary and posterior pituitary.

• A: TSH

• P: ADH

From which embryonic tissue is the nervous system largely derived from?

• ectoderm