NPB 101 UCD WQ26

Cumulative Review

Levels of Organism From Smallest to Largest

Atom → Molecule → Organelle → Cell → Tissue → Organ → System → Organism

What is the breakdown of Extracellular and Intracellular fluid?

33% Extracellular, 67% intracellular

What percent of the Extracellular fluid is interstitial fluid?

26%

What percent of the Extracellular Fluid is plasma?

7%

What is Interstitial fluid?

Fluid in between cells in the extracellular space

What are the four main tissue types?

MENC: Muscular, Epithelial, Nervous, Connective

What is the main function of Muscular Tissue?

Contractility

What is the primary function of Epithelial tissue?

Delimit, exchange, secretion

What is the main function of Connective Tissue?

Structural Support

What is connective Tissue made of?

Parenchyma & Stroma

What is Parenchyma?

Functional Cells

What is Stroma?

Supporting framework

What is the main function of Nervous Tissue?

Signal processing

What is homeostasis?

The maintenance of a dynamic steady state in an internal environment, where dynamic mechanisms detect and respond to deviations from a set point

What is required to achieve homeostasis?

A way to monitor a variable
A Set point
Ability to detect a change
Way to return the system to the set point

The combination of body components that work together to achieve homeostasis is called a:

Control System

What are the Three components of a control system

Sensors
Control Centers (a.k.a Integrator)
Effectors

What is the function of sensors

Monitor variable of interest and transform the info into a chemical/neural signal

What is the function of the Integrator (control center)

Compare registered value with set point
Create and send a signal to the appropriate body part (effectors)

What is the purpose of the Effectors

Undertake the change needed

What are the two ways that biological sensors act

1. They fall in a certain range of values

2. They fall out of range of values

In the Thermostat example, what is the control center?

thermostat

In the thermostat example, what is the heater?

Effector

In the thermostat example, what is the response?

Heat produced

In the Thermostat example, what is the room temperature monitor?

Sensor

In the thermostat example what signal is sent from the control center to the heater?

Efferent signal

In the thermostat example, what signal is sent from the room temperature sensor to the control center?

Afferent Signal

What is the Afferent Signal?

Sends information from the sensor to the control center/integrator

What is the Efferent Signal

Sends information from the control center (integrator) to the effectors that need to perform an action

In negative feedback, the controlled variable triggers a response that drives the variable in what direciton?

The opposite

In the room temperature regulation example, explain the role of the Thermometer, Thermostat, Furnace, Increasing Temperature

Thermometer: sensor
Thermostat: Integrator/Control Center
Furnace (heater): Effector
Increasing Temperature: Compensatory response

What are Intrinsic Control systems?

Control systems built into an organ or tissue (i.e vasodilation of tissues)

What are Extrinsic control systems?

Control systems that are outside an organ or system, permitting coordinated regulation of several organs (i.e blood pressure and blood glucose regulation)

Positive Feedback

you know this.

Feedforward Mechanism

Salivation, increased heart rate before working out,

What are the two methods of communicating signals?

Physical contact between cells (i.e gap junctions)
Secretion of chemicals/Substances(i.e neurotransmitters/hormones)

How do chemical signals reach their targets?

Passive Diffusion
Bulk Flow

What two organ systems are primarily responsible for maintaining homeostasis?

Nervous and Endocrine

What are the components of the central nervous system?

Brain
Spinal Cord
retina

What are the components of the Peripheral Nervous System?

Somatic
Autonomic

The autonomic peripheral nervous system is composed of which systems?

Sympathetic
Parasympathetic

Where do Somatic peripheral nerves come from?

Spinal cord

Spinal nerves are responsible for controlling

Motor and touch functions

Cranial nerves are responsible for

Motor and other sensory functions

From left to right, identify the specific planes:

Horizontal, Frontal/Coronal, Saggital

What structures make up the brainstem?

Medulla
Pons
Midbrain

What is the purpose of the brainstem?

Controls bodily functions and basic processes (heartbeat, breathing, etc.)

Ventral

Towards stomach

Dorsal

Towards the back

Rostral/Superior

Toward the head

Caudal/Inferior

Toward the tailbone

Medial

Towards Midline

Lateral

Away from Midline

Ipsilateral

Same side of midline

Contralateral

Opposite side of midline

What tissues protect the brain?

Meninges

What cell types make up the nervous system?

Neurons
Glia

What are Neurons?

Larger than glia
Communicate with other neurons
Long processes

What are Glia?

support neuron shape
Maintain ionic environment
Make myelin

What is the Plasma Membrane?

A phospholipid bilayer membrane enclosing each cell

What purpose do membrane proteins serve in the membrane?

Channels, transport of molecules
Receptors

What is the purpose of carbohydrates in the plasma membrane?

Adhesions and junctions

Mitochondria.

atp. metabolism.

Purpose of the cytoskeleton

Protein network for structural support, transport, and cellular movement

What are the three components of the cytoskeleton?

Microtubules
Microfilaments
Intermediate FIlaments

What is the purpose of Microtubules

Maintain Cell shape and control axonal transport, movement of cilia, flagella, and chromosomes (long hollow tubes)

Axonal Transport

Bidirectional movement of large molecules and vesicles along the axon of neurons

Anterograde

Away from the cell body

Retrograde

Toward the cell body

A retrograde tracer will reveal:

cell bodies

An anterograde tracer will reveal

Axons

Speed of Fast Anterograde:

50-400 mm/day

Speed of Fast Retrograde:

200-400 mm/day

Measuring the current at a certain membrane potential is called:

Voltage clamp

Positive Current

Flowing from inside the cell to outside the cell

Negative current

Flowing from outside the cell to inside the cell

What forces act on the ion?

Chemical
Electrical

At equilibrium potential, what two forces cancel out? (NO NET MOVEMENT)

Electrical and Chemical

What do IV plots show?

Relationship between the current (y-axis) and membrane potential (x-axis)

At rest, only NA+ and K+ can cross the membrane; what makes it so that the resting membrane potential is closer to the equilibrium potential of K+ instead of Na+

Leak channels

Resting potential for Na+

~+65 mV

Resting Potential for K+

~-90 mV

To prevent too much Na+ from leaking into the cell, what must be used?

Na/K pumps to pump Na+ out of the cell (uses ATP)

The Goldman-Hodgkin-Kats (GHK) equation takes into account what variables:

Permeability of ions
Concentration of Ions (Driving Force)

An activation potential only occurs once a _____ is reached

Activation threshold (~-55 mV)

Depolarization

Rise in membrane potential:

Voltage gated Na+ channels start to open after sequential synaptic potentials
Voltage-gated K+ channels open
Voltage-Gated Na+ channels begin to deactivate and close

Repolarization

Drop in membrane potential:

Voltage-gated K+ channels begin closing

Voltage-gated Na+ channels go from inactive to close

Hyperpolarization

Slight rise of membrane potential back to resting potential:

K+ pores open
Na+ leak channels

Action Potentials cannot carry a signal from just one single potential… so

it must propagate across the axon’s length

What can cause an action potential to move faster?

Depolarization of membrane:
Increase Axon diameter
Myelinate the axon (insulation)

Nodes of Ranvier

Places where voltage-gated channels are found n myelinated axons

What keeps an action potential from going inthe reverse direction?

Inactivation of voltage-gated Na+ channels

Absolute Refractory Period

The period that the voltage-gated Na+ channels are in the inactive state

Relative Refractory Period

The period that the voltage-gated Na+ channels are in the closed state and the voltage-gated K+ channels are still open

Why are Tetrodotoxins so dangerous?

Blocks voltage-gated sodium channels from opening, holding them closed

In normal conditions, what are the concentrations of Na+ and K+ in the cell?

K+ is more abundant in the cell
Na+ is more abundant OUTSIDE the cell

What do dendrotoxins do?

Block voltage-gated potassium channels of the motor neurons going to the muscles at the node of Ranvier

What is the path of an action potential release a neurotransmitter to another neuron?

Pre-synaptic neuron => AP => axon => axon terminal => release of Ca2+ => synaptic cleft => post-synaptic neuron

What prevents the neurotransmitter from acting on the receptor of the post-synaptic neuron again?

Enzymes in the synaptic cleft break down the neurotransmitter
Pre-synaptic neuron reuptakes unused receptor