Bio lab test 2

Question 1

Skeletal muscles

Answer 1

Contain specialized receptors which convey infor about muscle length, tension, and pressure to the central nervous system.

Question 2

Muscle spindles

Answer 2

The mechanosensory receptors responsible for provinding information about the length or the rate of change of the length of a muscle.

Question 3

What is a stretch (myotatic) reflex?

Answer 3

Spindles arranged parallel with muscle fibres and are stretched when an external force like a tendon tap stretches the muscle, causing excitation of its muscle spindles and results in a reflex contraction of the muscle.

Question 4

What are factors than result in minimal time delay from when muscle is stretched to when muscle contracts?

Answer 4

Stretch reflexes involve large diameter sensory axons and contain a small number of synapses in the circuit.

Question 5

Why do stretch reflexes have a monosynaptic pathway?

Answer 5

The sensory afferent nerves from the muscle spindles enter the spinal cord and synapse directly with motor neurons, rather than with interneurons. When motor neurons are triggered, they trigger contraction of the same muscle group. Same sensory neuron also synapses to an interneuron that connects to another neuron, stimulating antagonistic muscle group, completing reflex arc.

Question 6

Calf muscle group responsible for extension of the foot during the Achilles reflex

Answer 6

The calf muscle group is composed of the gastrocnemius (which
consists of two branches or heads) and the soleus (which lies underneath the gastrocnemius).
The gastrocnemius and soleus merge at the base of the calf and are joined to the Achilles tendon
by tough connective tissue.

Question 7

Why won’t dancers generate optimal results?

Answer 7

They work diligently on

their flexibility and may override muscle spindle activity.

Question 8

Downward movement of the foot

Answer 8

Plantar flexion

Question 9

Upward movement of the foot

Answer 9

Opposite of plantar, called dorsiflexion.

Question 10

Why must you multiply distance between belly of calf muscle and location of sensory motor synapse in spinal cord by two?

Answer 10

Signal travels to and from this location.

Question 11

Achilles monosynaptic? True or false?

Answer 11

Even though this stretch reflex is known as a monosynaptic reflex, the pathway also
includes the neuromuscular synapse.

Question 12

Conduction velocity

Answer 12

Assume synaptic transmission takes 0.5 msec, calculate conduction velocity in the nerves composing reflex pathway:
[total path length (m)]/[mean reflex time (sec) - synaptic transmission time] = conduction velocity m/s

Question 13

What does the strength of a striated muscle contraction depend on?

Answer 13

the amount of electrical activity in

the muscle.

Question 14

What did we use to measure grip strength?

Answer 14

A hand dynanometer - EMG activity from forearm.

Question 15

Motor neuron

Answer 15

Innervates groups of muscle fibres that make up vertebrate skeletal muscle. Single motor neuron has a branched axon, allowing it to innervate multiple muscle fibers (few to several thousand).

Question 16

Motor unit

Answer 16

The motor neuron and the muscle fibres it innervates.

Question 17

Motor unit contraction

Answer 17

When the motor neuron undergoes an action potential, all of the
associated muscle fibers are stimulated and contract. By increasing the number of active motor
units the strength or force of the muscle contraction will increase in a principle known as motor unit
recruitment.

Question 18

Maximal level of muscle activity

Answer 18

Since there is a finite number of motor units in each muscle, once all of the motor
units have been recruited no additional force can be generated. At this point we will observe a
plateau of muscle force as we reach the maximal level of muscle activity.

Question 19

Osmosis

Answer 19

Osmosis is the movement of water across a semipermeable membrane (biological or
artificial), from an area of low solute concentration (hypotonic or hypo-osmotic) to an area of
high solute concentration (hypertonic or hyperosmotic). Osmosis is a type of passive transport that requires that the membrane restrict the
movement of at least one solute but not water (i.e. be semipermeable).

Question 20

Isotonic

Answer 20

If the concentration of solute and water

become equal on either side of the membrane, the solution is deemed to be isotonic or iso-osmotic.

Question 21

Osmoregulation

Answer 21

Osmoregulation is
simply the regulation of water and ion concentrations in the body. Many biological membranes,
including the plasma membrane, are semipermeable. Solutes such as inorganic ions and large
organic molecules are incompatible with the plasma membrane structure and do not easily
cross the plasma membrane. In contrast, water is a relatively small molecule possessing high
kinetic energy and it moves freely across the plasma membrane along any solute gradient that
might be present.

Question 22

Why are the effects of osmosis are exceedingly important to animals, especially those from an
aquatic environment?

Answer 22

These animals live in direct contact with an aqueous solution, and the
membranes of their body surfaces are semipermeable. Thus, whole body water and solute
concentrations are influenced directly by their environment. Many aquatic animals possess
specific tissues and organs designed to regulate body (extracellular) water and solute
concentrations.

Question 23

Osmoregulators

Answer 23

Animals that maintain body solute concentrations different from the environment
are called osmoregulators. All freshwater animals are osmoregulators and are generally
hyperosmotic to their environment (low environmental salt content). Thus, freshwater animals
are faced with body weight gains and losses depending on the osmotic gradient that exists in
their environment.

Question 24

Osmoconformors

Answer 24

Some marine animals do not maintain their osmotic concentrations different
from the environment and are called osmoconformers. Sodium is the predominant cation in
the extracellular fluid of multicellular animals and in seawater. By osmoconforming, some
animals take advantage of the high level of Na+ in seawater so that minimal energy and body
structures are needed for osmoregulation. Generally, the large volume of water in the ocean
ensures minimal fluctuations of the osmotic environment and osmoconformers are usually
exposed to a relatively stable environment.

Question 25

Most osmoregulatory systems involve:

Answer 25

the active transport of ions across an epithelial surface, | with water following the ion gradient by osmosis.

Question 26

Terrestrial invertebrate blood concentrations

Answer 26

Evolved from freshwater or littoral ancestors, 250 - 500 mOsm (milliosmolar)

Question 27

Seawater milliosmolar concentration

Answer 27

1000 mOsm

Question 28

Two problems associated with osmoregulation for land invertebrates:

Answer 28

First, salts have to be consumed, as they are not readily available on land. Second, water must be obtained and preserved within the animal, since evaporation from the body will always occur. The external skin of terrestrial invertebrates functions to let oxygen in and carbon dioxide out as well as preventing water and ion loss. The internal tissues of annelids are hyperosmotic relative to the freshwater soil surroundings. As a result annelids take in water osmotically and produce hyposmotic urine to get rid of excess water.

Question 29

Metanephridia

Answer 29

In annelids, excretion and osmoregulation are accomplished by a highly developed organ system called metanephridia.

Question 30

Express body mass of each animal as percentage of initial mass:

Answer 30

Final weight/initial * 100. >100 means gained water.

Question 31

Blood plasma

Answer 31

The non-cellular fluid of blood. Isotonic relative to the cytoplasm of blood cells.

Question 32

Human respiratory system

Answer 32

consists of a series of tubes that branch and terminate as | clusters of small membranous air sacs called alveoli.

Question 33

Oxygen and CO2 rely on what to | cross the alveolar membrane?

Answer 33

simple diffusion

Question 34

Factors that influence diffusion of gases between lungs and the blood:

Answer 34

the amount of respiratory surface area, diffusion distance and concentration gradient.

Question 35

A high concentration gradient is ensured by:

Answer 35

(1) movement of blood with low O2 and high CO2 levels to the lungs and (2) pulmonary ventilation (breathing), which maintains a high level of O2 and a lower level of CO2 in the alveolar air.

Question 36

Tidal volume

Answer 36

The amount of air that moves in | or out of the lungs during any one breathing cycle is called the tidal volume (TV)

Question 37

inspiratory reserve volume

Answer 37

After normal inspiration, it is possible to breathe in additional air—this is called the inspiratory reserve volume (IRV)

Question 38

Expiratory reserve volume

Answer 38

Similarly, after a normal expiration, it is possible to exhale additional air from the lungs—this is the expiratory reserve volume (ERV).

Question 39

residual volume

Answer 39

Even if the expiratory reserve volume is fully expelled from the lungs, there is still a volume of air in the lungs, called the residual volume (RV) that cannot be exhaled. The RV has lower O2 and higher CO2 concentrations than atmospheric air. Upon inspiration, however, fresh air mixes with stale air from the RV, and the alveolar O2 and CO2 concentrations will be sufficient to facilitate diffusion of the gases to and from the capillaries.

Question 40

How is the amount of air moving to and from the respiratory surface of the lungs adjusted to meet the metabolic demands of the individual?

Answer 40

This is done by altering the TV as well as increasing | the frequency of breathing.

Question 41

Vital capacity

Answer 41

The maximal volume of air that can be exchanged during a single breathing cycle is called the vital capacity (VC) and represents the maximum TV possible for an individual. In this situation, all of the IRV and ERV are used to generate the maximum volume of air exchange in the lung.

Question 42

What regulates adjustments in the TV and breathing rate?

Answer 42

Adjustments in the TV and breathing rate are regulated by the brain’s respiratory center in the medulla oblongata.

Question 43

Perihpheral chemoreceptors

Answer 43

Peripheral chemoreceptors to detect blood pH, O2, | and CO2 levels

Question 44

Stretch receptors

Answer 44

stretch receptors in the lungs provide important sensory information that modulates the activity of respiratory center neurons.

Question 45

Spirometer

Answer 45

The quantity of air exchanged during lung ventilation can be measured using a volume recorder called a spirometer.

Question 46

Breathing rate (breaths/minute)

Answer 46

60 seconds/minute divided by mean breath period (sec/breath)

Question 47

Minute respiratory volume

Answer 47

Multiply mean tidal volume by breathing rate to calculate the volume of air passing through the subject’s lungs each minute.

Question 48

In healthy individuals, the ___ is usually about ___ of the ___.

Answer 48

VC, 75%, TLC (total lung capacity)

Question 49

True or false? RV cannot be measured using spirometer.

Answer 49

True. Must be estimated. TLC - VC

Question 50

Volumes within ___ of predicted volumes are normal.

Answer 50

20%. Greater, may simply point to need for more testing.

Question 51

Estimate of VC in liters

Answer 51

VC (Male) = (0.052H) - 0.022A - 3.60 | VC (Female) = 0.041H - 0.018A - 2.69

Question 52

Inspiratory capacity

Answer 52

TV+IRV

Question 53

Expiratory cpacity

Answer 53

TV+ERV

Question 54

Functional Residual Capacity

Answer 54

ERV+RV

Question 55

Total Lung Capacity

Answer 55

TV+RV+IRV+ERV

Question 56

The cardiac cycle in humans and other vertebrates involves the sequential contraction of the:

Answer 56

atria and the ventricles.

Question 57

The heart’s rhythmical contraction sequence is triggered by:

Answer 57

action potentials from myocardial cells that are conducted in a coordinated fashion throughout the entire heart.

Question 58

Where do electrical signals to initiate vertebrate heart contraction originate?

Answer 58

in the myocardial | cells, though several aspects of heart activity can be modified by the autonomic nervous system.

Question 59

What is Excitation or inhibition of the heart is accomplished by?

Answer 59

changes to the contraction rate and various other parameters associated with myocardial contraction. An obvious example is the increase in heart rate that occurs during exercise.

Question 60

Increased heart rate and reducing overall time that complete depolarization/repolarization cycle occurs

Answer 60

Increased heart rate (measured in beats per minute) is primarily accomplished by reducing the time between beats (i.e. the T-P interval) and the overall time that a complete depolarization/repolarization cycle occurs (i.e. the P-T interval). This latter effect is accomplished by altering the conduction velocity of the electrical signals as they travel throughout the heart.

Question 61

Pressure resevoir

Answer 61

Once ejected from the heart, blood enters the arterial system for distribution throughout the body. The arterial system functions as a pressure reservoir in that the amount of blood flow is directly related to the pressure difference along an artery. Increased heart function will increase centralized blood pressure, but signals from the autonomic nervous system can also control the BIOL 224 Lab 7: Page Copyright 2015- Tracy Marchant & Sheri Fisher 2 degree of contraction of the smooth muscle found in the walls of the arteries.

Question 62

Vasoconstriction/vasodilation

Answer 62

Once ejected from the heart, blood enters the arterial system for distribution throughout the body. The arterial system functions as a pressure reservoir in that the amount of blood flow is directly related to the pressure difference along an artery. Increased heart function will increase centralized blood pressure, but signals from the autonomic nervous system can also control the BIOL 224 Lab 7: Page Copyright 2015- Tracy Marchant & Sheri Fisher 2 degree of contraction of the smooth muscle found in the walls of the arteries.

Question 63

Flight or flight response

Answer 63

Autonomous N.S. influences heart rate directly - sympathetic NS releases epi from adrenal glands, heart beats faster. Parasympathetic releases acetylcholine from vagus nerve, bind to heart receptors, beat slower.

Question 64

baroreceptor reflex

Answer 64

Several peripheral feedback loops within the autonomic nervous system are used to simultaneously coordinate heart activity, arterial blood pressure and overall blood flow in the body. The baroreceptor reflex is one of the most important of these feedback loops. This reflex normally acts to ensure that central arterial blood pressure is maintained at a level appropriate for metabolic activities in the body, but that is not too high to cause rupture of arterial vessels or excess fluid leakage from the capillaries. used to coordinate heart activity, arterial blood pressure and peripheral blood flow.

Question 65

Diving

Answer 65

Diving in these animals generally causes selective peripheral vasoconstriction and a sharply reduced blood flow to the limbs, gut and the skin. This ensures that blood is delivered to organs with the highest need for oxygen, including the brain and heart.

Question 66

Diving bradycardia

Answer 66

the selective vasoconstriction that takes place during diving has the potential to cause a significant increase in the blood pressure of the central arteries. This is avoided by a baroreceptor-mediated response known as diving bradycardia, where heart rate is substantially reduced to ensure that blood pressure in central arteries does not exceed safe levels.

Question 67

Heart valves

Answer 67

The hearts sounds “lub dub” are made as valves within the heart close. As the valves close, a very small amount of blood is pushed backward through the valve. This creates a very short period of turbulence that can be heard through the stethoscope.

Question 68

Sphygmomanometer

Answer 68

The sphygmomanometer is the most commonly | used device to determine arterial blood pressure.

Question 69

heart rate (bpm)

Answer 69

60 s/m divided by second/beat