BIOL 252 Exam 1 Study Guide with Complete Solutions

BIOL 252 Exam 1 Study Guide with Complete Solutions Central Nervous System - Ans:-"general" of the body; integration of sensory input and origin of motor responses • brain • spinal cord Peripheral Nervous System - Ans:-body; sensory input and motor output • nerves • sensory receptors • motor neurons sensory receptors - Ans:-Afferent neurons → Admit signals differentiated based on location ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 2/70 • somatic • visceral somatic sensory receptors - Ans:-receptors and neurons that are located in the skin, skeletal muscle, joints visceral sensory receptors - Ans:-receptors and neurons that are located in internal organs motor neurons - Ans:-Efferent neurons → Exit/Effect signals - differentiated not based on location, but rather on the target organs • somatic nervous system • autonomic nervous system somatic nervous system - Ans:-system of neurons that enervate skeletal muscles autonomic nervous system - Ans:-system of neurons that enervate smooth and cardiac muscles; glands Santiago Ramon y Cajal - Ans:-discovered the neuron using a modification of Golgi's staining method that allowed Cajal to see the minutia of neurons and draw their anatomy ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 3/70 basic structure of a neuron - Ans:-- soma - dendrites - axon hillock - axon - myelin - terminal arbor - terminal buttons soma - Ans:-cell body - can receive inputs dendrites - Ans:-branching from the cell body of the neuron which have the major function of receiving inputs *D*endrite → *D*ownload axon hillock - Ans:-hump on the soma of a neuron from which the axon of the neuron extends ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 4/70 axon - Ans:-long singular stalk extending from the soma of the neuron which creates action potentials and sends inputs to other neurons *A*xon → *A*way myelin - Ans:-insulation present on some axons of the nervous system (not present on all axons); whitish fatty segmented sheath around mot long (NOT ALL) axons that increase the speed of nerve impulse transmission - cell has concentric layers of membrane that make up the myelin sheath - ONLY on axons (NOT dendrites, soma, etc.) but not all axons - made from Oligodendrocytes (CNS) and Schwann cells (PNS) - rather than one long piece of insulation, is multiple small pieces of insulation -- nodes of ranvier nodes of ranvier - Ans:-areas of the axon that is not covered in myelin, occurs between cells of myelin terminal arbor - Ans:-fine branching at the end of the axon ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 5/70 terminal buttons - Ans:-regions at the end of terminal arbor branches that release neurotransmitters into the synapse astrocytes - Ans:-• support and brace neurons • control the chemical environment • important physiological roles --- can secrete/absorb different molecules (i.e., ions) • most abundant cells in the brain (more than neurons) Oligodendrocytes - Ans:-insulators of the thick neurons of the CNS • one cell creates several units of myelin sheath and can insulate many different axons ependymal cells - Ans:-circulate the CSF satellite cells - Ans:-glial cells that surround somas of neurons in the ganglia; provide electrical insulation and regulate chemical environment of neurons microglia - Ans:-immune cells of the CNS Blood Brain Barrier (BBB) - Ans:-- astrocytes are important in telling the capillaries of the brain to form tight functions/inducing formation of BBB BUT are not part of the BBB themselves ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 6/70 - tight junctions between endothelial cells of the capillaries in the brain form the BBB • BBB is between the extracellular fluid (ECF) and the brain ciliated epithelial cells - Ans:-- lining the central cavities of the brain and spinal column - forming a permeable barrier between the CSF and nervous tissue cilia - Ans:-made of tubules; can be static or dynamic (beating) ependymal cilia are... - Ans:-dynamic (beating) which helps to move/circulate the CSF • without movement of CSF, there would be an accumulation which would lead to an over-sized brain (hydrocephalus) • ciliated epithelial cells also help create CSF Hydrocephalus - Ans:-excess cerebrospinal fluid • can be due to many things → lack of cilia, lack of drainage for CSF, etc. • treated by inserting a shunt and tubing leading to a cavity in the body (i.e., stomach) where the CSF can drain and be flushed leak/leakage (passive) channels - Ans:-• based on three dimensional configuration (3DC) • these channels are ion specific based on the shape (3DC) of the ions ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 7/70 • will only have inward channels and not outward channels • movement occurs based on concentration gradient so we only need one type of channel and the direction of flow will be determined by the concentration gradient • ions carry charge to in addition to concentration gradient there is also electrochemical gradient which will determine ion flow what will happen when there is more K+ inside than outside the cell? - Ans:-K+ will move outside the cell down it's diffusion gradient what will happen when there is more K+ and negatively charged proteins inside, only/less K+ outside the cell? - Ans:-• K+ leaves the cell via K+ leak channels due to the chemical gradient • negatively charged proteins cannot leave the cell • as K+ is leaving an electrical gradient starts to pick up, driving K+ back in • at some point an equilibrium is reached via a combination of electrical and chemical gradient • with regards to K+ the electrical gradient counteracts the chemical gradient membrane permeability to K+ vs Na+ - Ans:-membranes are much more permeable to K+ than to Na+ so sodium will flow but has a much lower impact on the membrane potential • K+ is found in higher concentrations inside the cell ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 8/70 -- membrane easily permeable to K+ • Na+ is found in higher concentrations outside the cell -- membrane less permeable to Na+ resting membrane potential is mainly dependent on... - Ans:-the K+ electrochemical gradient it is negative (-70 mV) BUT what creates the chemical gradient in the first place? - Ans:-the Na+-K+ pump restores the chemical gradients (works against the gradient) and therefore maintains the resting membrane potential the Na+-K+ pump requires... - Ans:-energy (ATP) to bring back the K+ that has just left and kick out the Na+ that has just entered • use 1 ATP (convert to ADP and phosphate) • returns 2 K+ • expels 3 Na+ all this is achieved by a movement of only a fraction of the ions involved (0.0006% of the K+ ions actually move) ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 9/70 if the pumps did not work... - Ans:-action potentials would be impossible because there would be no chemical gradient → all functioning would be impossible Summary of membrane info - Ans:-- the membrane is much more permeable to K+ than to Na+ - the electrical gradient counteracts the chemical gradient, and the ions