BIOL 273 - Unit 1

Question 1

Physiology

Answer 1

Study of the normal functioning of a living organism and its component parts

Question 2

Key concepts/themes important in understanding physiology

Answer 2

• Structure and function
• Biological energy
• Information flow
• Homeostasis

Question 3

Organizational levels from smallest to largest

Answer 3

1. Chemical - atoms and molecules
2. Cellular - neuron, lymphocyte
3. Tissue - collection of cells (connective)
4. Organ -structural unit made of tissues (heart)
5. Organ system - integrated group of organs
6. Organism - individual form of life

Question 4

Cells are held together by cell junctions…

Answer 4

anchoring junctions, gap junctions, tight junctions

Question 5

There are four primary tissue types in the human body

Answer 5

Epithelial, connective, muscle and neural

Question 6

Epithelial tissue

Answer 6

• protect the internal environment of the individual
• regulate exchange of material between environments
• epithelia consist of oneor more layers connected with basal lamina

Question 7

Five types of epithelia

Answer 7

1. Exchange - rapid exchange of material
2. Ciliated - line airways and female reproductive tract
3. Secretory - synthesize and release products into external
4. Transporting - selective transport of material
5. Protective - found on surface of the body

Question 8

Connective tissue

Answer 8

provides structural supprot and barriers
- extensive ECM containing proteoglycans, collagen, elastin and fibronectin

Question 9

Five types of connective tissue

Answer 9

1. Loose (elastic tissue)
2. Dense (strength the primary function)
3. Adipose (contains adipocytes)
4. Blood (watery matrix lacking insoluble protein fibers)
5. Supporting (dense substances)

Question 10

Muscle Tissue

Answer 10

Ability to contract to produce force and movement

Question 11

Three types of muscle

Answer 11

1. Skeletal (responsible for gross body movement)
2. Smooth (Responsible for influencing the movement of substances into/out of/within the body)
3. Cardiac (Found only in the heart, contraction moves blood through the body)

Question 12

Neural connective tissue

Answer 12

Carry information from one part of the body to another
- Very little ECM in neural tissue

Question 13

Two types of neural tissue

Answer 13

1. Neurons (carry info as electrical or chemical signals)
2. Gilal cells (supporting cells for neurons)

Question 14

“Function” in physiology

Answer 14

the “why” - why does the system exist

Question 15

“Mechanism” in physiology

Answer 15

the “how” - how does the system work

Question 16

How do physiologists study mechanism to understand function

Answer 16

how cellular and molecular changes affect the organism as a whole

Question 17

Homeostasis

Answer 17

a central organizing principle of physiology , the maintaenance of a relatively stable internal environment

Question 18

How does homeostasis involve a series of automatic control mechanisms

Answer 18

• Maintains a similar condition for all the cells of the body
• Achieved through the effects of different organ systems working together

Question 19

Acclimatization

Answer 19

Environmentally induced change in physiological function with no genetic change

Question 20

What is the result of homeostatic control

Answer 20

oscillation around a set point (which can change with time)

Question 21

Four Basic mechanisms of how cells communicate in the body

Answer 21

1. Gap junctions
2. Contact dependent signal
3. Local communication
4. Long-distance communication

Question 22

Gap junction communication

Answer 22

(direct cell-to-cell communication)
- via protein channels between adjacent cells
- gap junctions are capable of opening and closing

Question 23

Contact dependent signal communication

Answer 23

from the interaction between membrane molecules on two cells
- in immune cells

Question 24

Local communication

Answer 24

communication with neighbouring cells
- occurs via paracrine and autocrine signals on the neighbouring cells

(can also be gap junctions and contact-dependant signals)

Question 25

Autocrines

Answer 25

chemicals that act on the cell that produces them

Question 26

Paracrine example

Answer 26

histamine - paracrine signals are secreted by one cell and diffuse to adjacent cells

Question 27

Long distance communication

Answer 27

- responsibility of the nervous and endocrine systems - nervous system uses combinations of chemical and electrical signals (neurotransmitters) - endocrine system uses chemical signals (hormones)

Question 28

Why do some cells respond to a chemical signal and others do not

Answer 28

target cells have various receptor proteins , only respond to a chemical signal if they have right receptor

Question 29

Receptors

Answer 29

- usually transmembrane proteins (glycoproteins) - usually on plasma membrane but can be intracellular

Question 30

Three domains of membrane spanning receptors

Answer 30

1. Extracellular domain - involved in binding the ligand 2. Trans - membrane domain - hydrophobic 3. Intracellular (cytoplasmic domain) - involved in activating the cellular response

Question 31

Two ways homeostasis may be maintained

Answer 31

1. Local 2. long-distance pathways

Question 32

Local control of homeostasis

Answer 32

the effects are exerted on neighbouring cells, ex paracrine control of blood vessel diameter due to low O2

Question 33

Reflex control/ long distance pathways

Answer 33

The reaction in one or more organs controlled from elsewhere in the body - can be any long distance path of the nervous /endocrine system

Question 34

Three types of feedback/control systems to regulate the response loops

Answer 34

1. Negative feedback 2. Positive feedback 3. Feedforward control

Question 35

Negative feedback

Answer 35

- results in a change that opposes or removes the signal thus returning the variable to its original value - allows for homeostatic control - keeps a system near or at set-point - oscillation around the set point ex. blood pressure

Question 36

Positive Feedback

Answer 36

- response sends signal - reinforces stimulus sending the variable further from the set point until and external signal turns the response off - NOT homeostatic (response reinforces the stimulus) - sends system temporarily out of control ex. labour

Question 37

Feedforward Control

Answer 37

Anticipatory control: predicts that change is about to happen, starts the response loop -> prevent change

Question 38

Lipophilic hormones

Answer 38

chemical messenger signals carried by the bloodstream until they diffuse from the blood into interstitial fluid. - enter cells by simple diffusion through the phospholipid bilayer of the cell membrane [p. 134]. Once inside, they bind to cytosolic receptors or nuclear receptors - generate long term effects - intracellular receptors

Question 39

Lipophobic

Answer 39

cannot cross membranes by simple diffusion. Instead, the vast majority of solutes cross membranes with the help of membrane proteins, a process we call mediated transport. - cell membrane receptors

Question 40

Describe the endocrine system (long distance communication)

Answer 40

Hormones are secreted by endocrine glands or cells into the blood. Only target cells with receptors for the hormone respond to the signal

Question 41

Describe the nervous system

Answer 41

Neurotransmitters are chemicals secreted by