Physiology Midterm Lecture #1

Question 1

Summation

Answer 1

the process of adding up postsynaptic potentials and responding to their net effect
(Occurs in the trigger zone)

Question 2

Temporal summation:

Answer 2

occurs when a single synapse generates EPSPs so quickly that one is generated before other one fades

Question 3

Spatial summation

Answer 3

occurs when EPSPs from several different synapses add up to threshold at an axon hillock

Question 4

Presynaptic Inhibition

Answer 4

• releasesGABA

Prevents voltage-gated Ca2+ channels in synaptic knob (S) from opening and so little or no neurotransmitter is released

Question 5

Functions of the Skeleton

Answer 5

1. Support
   2.Protection
2. Movement
3. Electrolyte balance
   – calcium and phosphate levels
4. Acid–base balance
   6.Blood formation

Question 6

Osteogenic cells

Answer 6

tem cells that give rise to most other types of bone cells

Question 7

Osteoblasts

Answer 7

bone forming cells

– Found under the endosteum and periosteum on the bone surface

Question 8

Osteocytes

Answer 8

osteoblasts that have become trapped in the matrix they deposited
Lacunae cavities where osteocytes reside
Canaliculi–channels connecting lacunae

Question 9

Physiology of Osseous Tissue

Answer 9

• Metabolically active
• phosphorous
• calcium

Question 10

Mineral Deposition (mineralization)

Answer 10

• Crystallization process
• Calcium, phosphate, and other ions are taken from blood and deposited in bone - hydroxyapatite
• osteoblast

Question 11

Mineral Resorption

Answer 11

process of dissolving bone and releasing minerals into blood

-osteoclast

Question 12

Hypocalcemia

Answer 12

deficient calcium in blood
- results in changes in membrane potentials (muscle spasms)
this is caused by vitamin D deficiency

Question 13

Hypercalcemia

Answer 13

• excessive calcium levels results ion channels less responsive

Question 14

What Parathyroid hormones maintain norm blood calcium concentration?

Answer 14

Calcitriol (most active from is VD) and calcitonin

Question 15

Calcitriol raises blood by

Answer 15

increase of Ca by the small intestine
increases Ca by skeleton
kidney reabsorption of Ca

Question 16

Calcitonin decreases blood by

Answer 16

secreting C cells of thyroid glands

Question 17

Homeostasis

Answer 17

the ability to detect change,activate mechanisms that oppose it, and thereby maintain relatively stable internal conditions

Question 18

Claude Bernard (1813–78)

Answer 18

Noted fairly constant internal conditions

Question 19

Walter Cannon (1871–1945)

Answer 19

Coined the term homeostasis

Question 20

Negative Feedback

Answer 20

allows for dynamic equilibrium within a limited range around a set point

Question 21

Heat-losing Mechanism

Answer 21

If too warm, vessels dilate in the skin and sweating begins

Question 22

Heat-gaining mechanism

Answer 22

If too cold, vessels in the skin constrict and shivering begins

Question 23

Homeostasis
Receptor
Integrating center
Effector

Answer 23

Receptor– structure that senses change in the body

Integrating (control) center– processes the sensory information, “makes a decision,” and directs the response

Effector
– cell or organ that carries out the final corrective action to restore homeostasis

Question 24

Positive Feedback and Rapid Change

Answer 24

loop causes a self-amplifying cycle where a physiological change leads to even greater change in the same direction
birthing

Question 25

Nervous system communication:

Answer 25

communicates by electrical and chemical means to send messages from cell to cell

Question 26

Endocrine system communication:

Answer 26

communicates by means of chemical messengers (hormones) secreted into to the blood

Question 27

CNS

Answer 27

Brain and spinal cord – Enclosed by cranium and vertebral column

Question 28

PNS

Answer 28

all other nerves besides brain and spinal cord

Question 29

Nerve

Answer 29

a bundle of nerve fibers(axons) | wrapped in fibrous connective tissue

Question 30

Ganglion

Answer 30

a knot-like swelling in a nerve where neuron cell bodies are concentrated

Question 31

Sensory (afferent) Division of the PNS

Answer 31

Carries signals from receptors to CNS Somatic - carries signals from skin, muscles, joints Visceral - "" heart, lungs

Question 32

Motor (efferent) division of the PNS

Answer 32

carries signals from CNS to effectors Somatic - '' skeletal muscles Visceral - carries signals to glands, cardiac and sm

Question 33

Properties of a Neuron

Answer 33

Excitability- ability to respond to a stimuli Conductivity- produce electrical signals to other cells Secretion - secretes a neurotransmitter

Question 34

Dendrites:

Answer 34

Primary site for receiving signals from Nucleus other neurons

Question 35

Soma:

Answer 35

control center of neuron – aka cell body

Question 36

Axon (nerve fiber)

Answer 36

Specialized for rapid conduction of signals to distant points

Question 37

Synaptic knob (terminal button):

Answer 37

junction (synapse) with the next cell

Question 38

Myelin Sheath

Answer 38

Formed by oligodendrocytes in CNS and Schwann cells in PNS

Question 39

Electrophysiology

Answer 39

study of cellular mechanisms for producing electrical potentials and currents

Question 40

Electrical Potential

Answer 40

a difference in concentration of charged particles between one point and another -cells are polarized, more negative on the inside of the membrane than outside

Question 41

Electrical Current

Answer 41

a flow of charged particles from one point to another

Question 42

Resting Membrane Potential

Answer 42

due to the unequal distribution of ECF and ICF 1. Ions diffuse down their concentration gradient 2. Plasma membrane is selectively permeable 3. Electrical attraction of cations (+) and anions (-) to each other

Question 43

Characteristics of Actions potentials

Answer 43

1. All or None 2. Nondecremental - does not get weaker with distance 3. Irreversible

Question 44

Refractory Period

Answer 44

a few ms after it is difficult or impossible to stimulate that region. The period of resistance to restimulation

Question 45

Absolute refractory period

Answer 45

no stimulus of any strength will trigger AP | last as long as inactivated Na+ gates are closed

Question 46

Relative refractory period

Answer 46

Only very strong stimulus will trigger new AP, last until hyper-polarization ends

Question 47

Saltatory Conduction

Answer 47

signal seems to jump from node to node

Question 48

Speed Conduction of Nerve Fibers

Answer 48

Diameter of fiber - large fibers have increased SA = more rapid signals Myelin = faster signal conductions

Question 49

What ions are more abundant inside and outside the cell?

Answer 49

K+ concentration is higher inside the cell | Na+ is higher outside the cell