Chapter 3 - Cell function Flashcards
Efferent Signal
(E)fferent - exit the brain
Afferent signal
(A)fferent - arrive at the brain
Smallest unit of brain function
golgi said it was reticular theory (continuous network of interconnected fibers (neurites) that form a mesh-like structure)
Cajal said neuron was the smallest (correct)
Neurons found in the Cerebral Cortex
Pyramidal makes up 2/3 of cerebral cortex
pyramid-shaped cell bodies and are key players in the brain’s neural circuitry
Neurons found in the Cerebellum
Purkinje Cells - long branching dendrites
Granule Cells (most abundant in brain) - single dendrite that makes connections with Purkinje cells
Internerouns
CNS in spinal cord. go between neurons in spine. involved in processing information, reflexes, and modulation of neuronal circuits.M
Motor Neurons
play a crucial role in the nervous system by transmitting signals from the central nervous system (CNS) to muscles and glands, facilitating movement and various bodily functions.
name and function of all the glial cells of the PNS
Schwan cells - myelinate the axon of neurons in the PNS
Satellite cells - regulate neurotransmitters in the PNS
name and function of all the glial cells of the CNS
oligodendrocytes - myelinate the axons of neurons in the CNS
Ependymal cells - secretes Cerebrospinal fluid (nourishes, waste management, protection)
Microglia - immune response of CNS
Astrocytes - maintain BBB and help in repairs
process of fixing a cut neuron in the PNS
if a neuron (PNS) is cut, Schwan cells will form a path for the neuron to reach out to.
when the axon is grown, the Schwan cells for a new myelin sheath
What is in the cell nucleus
Chromosomes 46
44 autosomes
2 sex chromosomes
Human genome project
completed in 2003
Complete genome of a human
-everything that makes a person
- less than 30,000 genes
(they estimated 100k before)
big to small
cell nucleus -> chromosome -> gene -> nitrogenous bases
why are nitrogenous bases important in building proteins
nitrogenous base tells what amino acid sequce to build a protein
stages of making a protien
amino acid chain ->
B sheet or a helix ->
protein ->
more complex protein (if combined)
where does translation happen typically
ER
otherwise at ribosomes that are just chillin in the cytoplasm
which base is used instead of thymine
uracil
How does protein packaging and transporting work?
Formed in the ER and wrapped up
attched to a motor molecule that moves along a microtuble to be implemented into the membrane or excreted via exocytosis
what are channels made of??
proteins
what is a wild type?
natural tendacy of a trait (right handedness 90%)
What is a Transgenic Technique?
Transgenic organism: genome has been altered (inserting/removing DNA a gene or genes).
Knock-in Technique**
“knocking in” a specific gene precise location. to see what protiens contribute to fur colour in mice
- Done at the embryonic stage, allowing changes to be inherited
Why is the Knock-in Technique good?
since our brain is structurally similar across species, we can test what is causing diseases (alzheimer’s, parkinsons)
Tay-Sachs Disease
- *Recessive gene
- inherited birth defect
- 4-6 mth after birth gets brain damage
- death by age 5
Huntington’s Disease
- motor and cognitive disturbances
- *Dominant gene (chromosome 4)
- dementia for kids
What is Apraxia
Neuro disorder is sometimes caused by mutation of the FOXP2 gene.
Results in…
loss of motor function
loss of speech
caused by family members carrying the gene mutation
Gene therapy
there are 2 methods of gene therapy
- Gene augmentation (add/replace)
- Gene suppression (add/remove to inhibit)
they use can use Viral Vectors to do this or injecting liposomes direclty
What example of Gene Therapy did we watch in class
Rhys Evans
born with (SCID) Severe Combined ImmunoDeficiency
Potential complications to effective gene therapies
- Immunotoxicity - T-cells overreact
- Mutagenesis - alteration of a patient’s DNA in a harmful way
- heritable changes, meaning the offspring of the treated individual may inherit the modified gene, leading to unintended long-term consequences.
Epigenetics
Epigenetic modifications can be influenced by a variety of factors, including development, environmental influences, diet, stress, and exposure to toxins.
Epigenetic Drift
Nature vs. Nurture in Twins
Epigenetic Mechanisms
Histone Mods:
- Alters chromatin structure (loosening or tightening)(open for transcribing)
DNA Modification:
- Silences gene expression by preventing transcription factor binding (methylation)
mRNA Modification:
- Regulates mRNA stability, translation, and degradation (could prevent translation)
How can Stress/Depression effect Epigenetics?
Stress = epigenomic change = changes in behaviour
SLC6A4 (serotonin reuptake)
BDNF (neuron growth & survival)
SLC6A4
(serotonin reuptake)
BDNF
(neuron growth & survival)
brain derived neurotrophic factor
