Week 2: Structure & Function of Cells

Question 1

cell

Answer 1

basic units of the structure and function of living things
*First coined by Robert Hooke in 1665
*Honeycomb appearance

Question 2

Cell Theory

Answer 2

*All organisms are made of one or more cells
*All life functions occur within cells
*All cells come from already existing cells

Question 3

Nerve cells (Neurons)

Answer 3

cells of the nervous system that generate electrical signals (action potentials) which allow them to communicate.
*They have a nucleus (vs. prokaryote cells)
*They do not renew themselves

Question 4

Neurons based on function:

Answer 4

Sensory
Motor
Interneuron/Relay

Question 5

Sensory Neuron

Answer 5

*Soma located in PNS
*Detects changes in the external and internal environment and sends info to CNS

Question 6

Motor Neuron

Answer 6

Soma located within the CNS
*controls muscle contraction and secretion of glands

Question 7

Relay/ Interneuron

Answer 7

*Located in CNS within neuronal structures
*Connect somatic and motor information 11

Question 8

Neurons based on structure:

Answer 8

Unipolar/Pseudo-unipolar
Bipolar
Multipolar

Question 9

Unipolar / Pseudo-unipolar

Answer 9

One process. Sensory neurons (spinal/cranial nerve ganglia)

Question 10

Bipolar

Answer 10

Two processes. Usually sensory neurons (e.g.retinal cells), also interneurons

Question 11

Multipolar

Answer 11

Multiple processes. Most common neuron in the CNS

Question 12

Plasma/ Cell Membrane

Answer 12

Structure
*Pliable lipid bilayer
*Selectively permeable *Embedded proteins

Function
*Protects inner cellular environment
*Regulates molecules that enter and exit the cell
*Passive Transport vs. Active Transport

Question 13

Cytoplasm

Answer 13

*Made up of cytosol and organelles
- Place of chemical reactions
*In motion, moving material from one part of cell to other

Question 14

Cytosol

Answer 14

Thick, jelly-like substance ~ 80% water

Question 15

Organelles

Answer 15

membrane-enclosed bodies within the cell

Question 16

Nucleus

Answer 16

“Control center” of the cell
*Contains chromosomes/DNA/genes
*DNA contains genes that each cell uses to make thousand of proteins, enabling the cell to survive
*It directs many of the cell’s activities

Question 17

Mitochondria

Answer 17

Powerhouse of cell –creates more than 90% of cellular activity
*Produces ATP
*DNA material present
*Necessary to sustain life and support growth
*Mitochondrial failure causes cell injury that leads to cell death.

Question 18

Endomembrane System

Answer 18

Endoplasmic reticulum
Golgi Apparatus
Lysosomes

Question 19

Endoplasmic reticulum

Answer 19

Location for synthesis of proteins (RER) and lipids i.e. Ribosomes

Question 20

Ribosomes

Answer 20

organelles in the cytoplasm and within the RER which synthesizes proteins for the cell

Question 21

Golgi Apparatus

Answer 21

organelle that packages the products synthesized by the ER (proteins, lipid molecules)

Question 22

Lysosomes

Answer 22

organelle that breaks down damaged cellular components or foreign material. Also facilitates apoptosis

Question 23

Cytoskeleton

Answer 23

Cytoskeleton is part of cytoplasm which is important for cell shape and movement

Question 24

Microtubles

Answer 24

*A long strand of bundles of protein filaments (tubulin)
*Involved in transporting substances from place to place within the cell and along the axon.

Question 25

Axoplasmic transport (aka axonal transport): Anterograde

Answer 25

soma -> periphery

Question 26

Axoplasmic transport (aka axonal transport): Retrograde

Answer 26

periphery towards soma

Question 27

Glia cell / Neuroglia

Answer 27

*The “glue” of the nervous system *Smaller in size than neurons *Various roles: support neurons, modulate neuron communication, and maintains homeostasis of the nervous system

Question 28

Types of Glial cells

Answer 28

(S A M E O S) CNS: Ependymal Astrocytes Oligodendrocytes Microglia PNS: Satellite Schwann

Question 29

Ependymal cells

Answer 29

Lines each of the 4 ventricles and spinal cord *Filters blood to make CSF

Question 30

Astrocytes

Answer 30

*Physical support to cell *Repair damage to tissue *Controls chemical environment *Fosters neural communication (tripartite synapse) *Nourishes cells

Question 31

Microglia

Answer 31

*Smallest of glia *Macrophage of the CNS *Immune defense

Question 32

Oligodendrocytes

Answer 32

*Myelin sheath of the CNS

Question 33

Satellite cells

Answer 33

*Surround sensory neurons, sympathetic and parasympathetic ganglia *Regulate extracellular space *Activated in response to tissue damage –aid in repair of damaged tissue and muscle repair

Question 34

Schwann cells

Answer 34

*Provide myelin sheath to axons in the PNS *Each myelin “segment” is made up of a single Schwann cell

Question 35

Degradation of microglia

Answer 35

*Compromised immune function of the brain *Neurological disorders

Question 36

Degradation of oligodendrocytes

Answer 36

*ALS *MS *Dementia *Schizophrenia

Question 37

*Degradation of astroglia

Answer 37

*Synaptogenesis *Neurodegeneration *Seizure disorder

Question 38

The Blood-Brain Barrier (BBB)

Answer 38

➢Discovered in 19th century: Ehrlich & Goldman injected colored dyes into blood stream versus CSF ➢Lina Stern coined BBB and described selective permeability *A physical barrier between the brain and blood *Made up of capillaries (endothelial cells) that form tight junctions *Semi-permeable barrier *Passive diffusion of oxygen, carbon dioxide, small uncharged molecules, lipid soluble molecules *Active transport for glucose, amino acid, choline, iron, hormones

Question 39

BBB Functions

Answer 39

*Protection: prevents easy access of pathogens, toxins and harmful metabolites *Homeostasis: regulates movement of Na+ and K+ *Nutrition: allows transport of glucose Circumventricular Organs: Allows the brain to monitor the physiological status of the body and regulation of endocrine function

Question 40

BBB Compromised by:

Answer 40

*Radiation *Hypertension *Infection, trauma/inflammation