EXAM1 NSC3361

Nucleus

Nucleus

Double membrane, contains DNA (some RNA), site of transcription

Cytoplasm

Location of organelles, contains freely soluble proteins; site of translation

Endoplasmic Reticulum

Attached to nuclear membrane

Rough ER

Embeded with ribosomes

Smooth ER

Not embedded with ribosomes

Ribosomes

Site of protein synthesis

Golgi Apparatus

Site of posttranslational modifications, protein sorting, protein packaging

Mitochondria

Site of cellular respiration, ATP production

Interphase

Growth phase of the cell and includes DNA replication

Mitosis

Divison of the nuclear material (DNA)

Cytokinesis

Divison of the cytoplasm

Adenosine triphosphate (ATP)

Generated by cellular respiration

Cellular Respiration

Comprised of glocolysis, the citric acid cycle, and the electron transport chain

Energy used to synthesize ATP

Transfer of electrons released from bonds being broken in organic molecules

Glycolysis Location

Occurs in the cytoplasm

Citric acid cycle and electron transport chain location

OCcurs in the mitochondria

ATP is generated by two mechanisms

Subtrate level and oxidative phosphorylation

Substrate Level phosphorylation

Glycolysis and pyruvate oxidation and the citric acid cycle

Oxidative phosphorylation

Use of protein gradient to form ATP, uses electron transport and chemiosmosis, most ATP is generated by this

Glycolysis

Breaks down glucose into two pyruvate, pyruvate is converted into acetyl CoA which is fed into citric acid cycle

Citric Acid Cycle

Provides energy for OxiPhospho, completes the breakdown of glucose

FADH and NADH

Electron Carriers that shuffle electrons gathered frmo glycolysis and citric acid cycle to electron transport chain

Electron Tranposrt Chain

Pumps H+ to outside of inner mitochondria membrane then diffuses it back (chemiosmosis) in order to power ATP synthase that synthesizes ATP from ADP. O2 is final electron acceptor to form water

Electron transport chain location

Located in the inner membrane of the mitochondria

Nucleic acids

Include DNA and RNA, nucleic acids are formed from nucleotide bases (ACGT)

DNA

Composed of nucleotides, each consisting of a sugar phosphate group and a nitrogen-containing base

Base Pairing in DNA

The DNA strand is held together by hydrogen-bonding

RNA differs from DNA

RNA is single-stranded, RNA contains a ribose sugar instead of deoxyribose, RNA contains uracil instead of thymine

DNA replication

Precedes cell division, once helix uncoils each nuceotide strand acts to serve as template, A with T and G with C s

DNA to RNA Transcription

DNA is transcribed into RNA, uracil replaces thymine. Occurs in Nucleus

mRNA Translation

Used as template for making a protein, occurs in the cytoplasm

mRNA read in triplet bases

"one strand of DNA serves as a template for transcription, mRNA becomes attached to ribosomes where tRNA read the codon to determine which amino acid should be added. mRNA read in 5' to 3' direction"

Genes

Basic unit of heredity is a sequence of DNA nucleotides on a chromosome

Chromosomes

Consists of a molecule of DNA and its associated proteins, In nondividing cell most chromosomes appear as chromatin

Chromsomes

Humans have 46 of these, sex cells have 23. DNA is wrapped around proteins called histones, chromsomes consists of two sister chromatids. Two sister chromatids are attached at center at centromere

Chromosomes location

Chromsomes are located in the nucleus

Autosomes

Include all chromsomes except the sex chromsomes, 22 pairs in humans

Sex chromosomes

depend on whether organism is male or female. females have XX males have XY

Diploid

Cells or organisms having paired chromsomes are diploid and shown as 2n. humans have diploid number of 2n = 46

Haploid

Only one set of chromsomes shown as n, sex cells are haploid or n

Mitosis Phases

prophase metaphase anaphase and telophase

Prophase

Chromsomes condense, centrosomes move , mitotic spindle forms

Metaphase

Chromosomes line up in the center of cell (equatorial plane)

Anaphase

Sister chromatids separate forming daughter chromosomes

Telophase

The nucleus reforms, chromsomes begin to uncoil, and the mintotic spindle disappears

Meiosis

Reduces the chromsomal number by half and introduces genetic variation

Meiosis I

Homologous chromsomes seperate

Meiosis II

Sister chromatids seperate

Meiosis is much different from mitosis

3 reasons: During prophase duplicated chromosomes pair up and crossing over occurs, Chromsomes line up as pairs of homologs not as individual chromosomes, Duplicated chromsomes move towards opposite poles but sister chromatids stay attached

Neurons

"Main functional cells of the nervous system, capable of generating electric signals ""action potentials"""

Glia

Glial cells are more numerous than neurons, tend to serve a more supportive role

Neuron Doctrine

Each neuron is its own entity, isolated from its neighboring neurons by small amounts

Reticular Theory

Neurons are not distinct units, but are fushed together

Two major problems impeded the progress of neuroscience

Small size of neurons solved by compound microscope. Ability to view nervous tissue fixed by fixation and stains.

Input zone (dendrites)

Extensions of the soma that receive incoming information

Integration zone (cell body/soma)

The main part of the neuron, housing the nucleus and much of hte cellular organelles

Conduction zone (axon)

Long extension that carries information away from the soma towards axon terminals

Output zone (axon terminals/boutons)

Housing transmitter(s), the chemical signals or message between neurons and target tissues

Signaling within neuron

Electrical nature and travels largely in one direction. Signaling usually travels from dendrites to the axon hillock (where the axon originates from the cell body or soma)

Neuron communication

Synapse is composed of presynaptic membrane to a synaptic cleft to postsynaptic membrane.

Neurons have 3 basic shapes

Neurons have same basic parts, but they dont all look exactly like

Multipolar neurons

Numerous dendrites and a single axon and are the most common

Bipolar neurons

Single dendrite at one and a single axon at the other end, common in sensory systems

Unipolar neurons (monopolar neurons)

Single process that extends from the cell body and brances in two different directions, where one branch is input and other output

Sensory neurons

Detecting and transmitting changes inside and outside the body to the brain

Interneurons

For integration; processing and interpreting sensory information; includes most of the neurons in brain

Motor neurons

Executing a response or responses to sensory stimuli via effectors (muscles and glands)

Glia functions

Glia serve various functions, much of it in support of neuronal function

Astrocytes

Act to regulate extracellular environment, help in forming the BBB

Microglia

Act as the immune cells of the brain

Ependymal cells

Lime the ventricles and secrete cerebrospinal fluid

Oligodendrocytes

Responsible for myelination in the CNS

Schwann cells

Responsible for myelination in the PNS

Satellite cells

Surround cell bodies of sensory neurons

Myelination of axons

Myelinated axons conduct electrical signals much faster, electrical signal can jump between nodes of Ranvier

Multiple Sclerosis

Autoimmune disease that attacks the myelin of axons, causing them not to properly function

Nervous system anatomical divison

Divided into central nervous and peripheral nervous system

Central nervous system

Includes the brain and spinal cord

Peripheral nervous system

Includes nerves, ganglia, sensory organs, everything outside the CNS basically

Somatic Nervous system

Part of the Peripheral nervous system. Innvervates skeletal muscle and sensory systems (it is largely under voluntary control)

Autonomic nervous system

Part of the CNS that innervates cardiac muscle, smooth muscle, and internal viscera (largely under involuntary control)

SNS leaving spinal cord

Leaves ventral root and directly innervates skeletal muscle

ANS leaving spinal cord

Leaves ventral root as preganglonic axon then passes through ganglionic neuron that leaves as post ganglionic axon. Doesnt dirrectly innervate tissue

ANS split into two functional divisions

Sympathetic and parasympathetic nervous system, most organs and or tissues receive innervation from both

Sympathetic nervous system

"Exit the CNS at the thoracic and lumbar levels. Prepares body for ""fight and flight"""

Parasympathetic nervous system

"Fibers exit the CNS at the brain steam and sacral levels. Prepares body for ""rest and digest"""

Cranial nerves

Serve to innervate the head, neck, visceral organs directly. Doesnt go through the spinal cord. Some of the cranial nerves are mixed, several are exclusively sensory or motor only.

Spinal nerves

Information flow to and from the periphery occurs largely through spinal nerves. Exit the spinal column bilaterally and are named for the part of the spinal cord they are connected to. Mixed nerves carry both motor and sensory.

Lumbar puncture

Enter needle into lumbar cistern in order to obtain cerbral spinal fluid for testing

Spinal cord color

Cell bodies of motor dibers are located within gray matter.

Dorsal root ganglia

Houses the cell bodies of sensory afferent fibers.

Nervous System derivation

Formes from ectodermal tissue during neurulation.

Gastrulation

Process by whihc the embryonic germ layers are formed during blastulation (the formation of a sphere with a fluid filled cavity)

Endoderm

Gives rise to the digestive and respiratory tracts

Mesoderm

Gives rise to the skeletal system as well as muscles

Ectoderm

Gives rise to skin and the nervous system

Neurulation

Neural plate becomes the neural tube (around 22 days post)

Forebrain (prosencephalon)

Gives rise to the telencephalon (cerebrum) and dienephalon (thalamus and hypothal)

Midbrain (mesencephalon)

Virtually stays the same

Hindbrain (rhombencephalon)

Gives rise to the metencephalon (pons and cerebellum) and the myelencephalon (medulla)