Lecture 12- Physiology and homeostasis

Question 1

Where do cells of multicellular organisms get their nutrients from?

Answer 1

Extracellular fluid that makes up the internal environment

Question 2

What makes complex multicellular organisms possible?

Answer 2

Physiological systems that maintain a stable internal environment

Question 3

How is it possible that animals can occupy habitats that would kill cells if exposed directly?

Answer 3

Stable internal environment protects cells from harsh environments or changes

Question 4

What is homeostasis?

Answer 4

The maintenance of a stable conditions within a narrow range in the internal environment

Question 5

What does homeostasis require to prevent cell damage or death?

Answer 5

Physiological regulation

Question 6

By what systems are physiological systems controlled?

Answer 6

Nervous system

Endocrine system

Question 7

What is required for regulation of the internal environment?

Answer 7

Information

Question 8

What is a set point?

Answer 8

A reference point at which the system is set

‘The threshold sensitivity to the feedback stimulus’

Question 9

What is feedback information?

Answer 9

Information relevant to the rate of a process that can be used by a control system to regulate that process at a particular level

Question 10

What is an error signal?

Answer 10

A signal produced when the set point and feedback information do not match

Question 11

What is feedforward information?

Answer 11

Information that can be used to alter the setpoint of a regulatory process. This suggests corrective action that needs to be taken.

Question 12

What are effectors?

Answer 12

Any organ, cell, or organelle that alters the environment. These effect changes in the internal environment.

Question 13

What are effectors controlled by?

Answer 13

Controlled systems

Question 14

What do regulatory systems do?

Answer 14

Systems that obtain, process and integrate information then issue commands to control the system

Question 15

Define regulatory system.

Answer 15

A system that uses feedback information to maintain a physiological function or parameter at an optimal level.

Question 16

What do sensors do?

Answer 16

Provide feedback information that is compared to the internal set point

Question 17

Define negative feedback.

Answer 17

Information relevant to the rate of a process that can be used by a control system to return the outcome of that process to an optimal level

Question 18

What effect does negative feedback have on a physiological system?

Answer 18

Tends to return a variable of the internal environment to the set point from which it deviated.

Question 19

What are the three types of sensory information in a regulatory system?

Answer 19

Negative feedback
Positive feedback
Feedforward information

Question 20

What effect does positive feedback have on a physiological system?

Answer 20

It amplifies a response (increases deviation from a set point)

Question 21

What affect does feedforward information have on a physiological system?

Answer 21

It anticipates internal changes and changes the set point

Question 22

Give an example of regulatory systems that use positive feedback.

Answer 22

• Responses that empty body cavities- urination, defecation, sneezing, vomiting
• Sexual behavior which causes more stimulation

Question 23

What are physiological systems made of?

Answer 23

Cells, tissues and organs.

Question 24

What is a tissue? What are the 4 kinds of tissue?

Answer 24

An assemblage of cells

• Epithelial
• Connective
• Muscle
• Nervous

Question 25

What is epithelial tissue?

Answer 25

Sheets of densely packed, tightly connected epithelial cells that cover inner and outer body surfaces and act as barriers and provide transport

Question 26

Where is epithelial tissue found?

Answer 26

Skin | Lining surfaces of hollow organs in the body- such as the gut

Question 27

What 5 roles do epithelial cells play in the body?

Answer 27

- Secretion of substances (hormones, milk, mucus, digestive enzymes, sweat) - Movement of substances with cilia - Receptor cells to provide information to the nervous system (smell and taste receptors) - Create boundaries- inside and outside of the body, between body compartments, line blood vessels, ducts and tubules - Control filtration and transport (molecules and ions that leave the blood, urine etc.)

Question 28

What is muscle tissue?

Answer 28

Elongated cells that can contract to generate forces and cause movement

Question 29

What tissue type is most abundant in the human body?

Answer 29

Muscle tissue

Question 30

What are the three types of muscle tissue?

Answer 30

Skeletal Cardiac Smooth

Question 31

What is skeletal muscles responsible for?

Answer 31

Locomotion, breathing, shivering

Question 32

What type of control is skeletal muscle under?

Answer 32

Both conscious and unconscious control

Question 33

What is cardiac muscle?

Answer 33

Makes up the heart, responsible for heart beat and pumping of blood.

Question 34

What is smooth muscle responsible for?

Answer 34

Movement and generation of forces in many hollow internal organs such as the gut, bladder and blood vessels

Question 35

What controls smooth and cardiac muscles?

Answer 35

These are unconscious- they are controlled by physiological regulatory systems.

Question 36

What is connective tissue?

Answer 36

Dispersed populations of cells embedded in an extracellular matrix that they secrete. Composition and properties differ among connective tissue types

Question 37

What does the extracellular matrix of connective tissue contain?

Answer 37

Protein fibers. - Collagen - Elastin

Question 38

What percentage of total body protein does collagen make up?

Answer 38

25%

Question 39

What properties of collagen make is a useful protein in the extracellular matrix of connective tissues?

Answer 39

Fibers are strong and resistant to stretch | This gives strength to the skin and connections between bones and muscles

Question 40

What role does collagen play in organs?

Answer 40

The fibers provide a net-like framework for organs, giving them shape and structural strength

Question 41

What are the properties of elastin?

Answer 41

It can be stretched several times its resting length and then recoil

Question 42

Where is elastin commonly found?

Answer 42

In tissues that are regularly stretched such as walls of lungs and large arteries.

Question 43

Name three types of connective tissues.

Answer 43

Cartilage, bone, adipose tissue

Question 44

What is the structure of cartilage?

Answer 44

A network of collagen fibers is embedded in a flexible matrix consisting of a protein-carbohydrate complex along with a specific type of cell called a chondrocyte

Question 45

What is the function of chondrocytes?

Answer 45

They secrete an extracellular matrix rich in collagen fibers and elastin fibers

Question 46

What properties of cartilage makes it a good connective tissue?

Answer 46

It is resistant to compressive forces- lines the joints of vertebrates It is flexible- it provides structural support for flexible structures (external ears, nose)

Question 47

Describe the structure of bone.

Answer 47

Contains lots of collagen fibers | Hardened by deposition of the mineral calcium phosphate

Question 48

What is adipose tissue?

Answer 48

A form of loose connective tissue that includes adipose cells, which form and store droplets of lipids

Question 49

What is adipose tissue a source of? What are its other functions?

Answer 49

Stored energy | Cushion organs, barrier to heat loss.

Question 50

What is blood?

Answer 50

A connective tissue that consists of cells dispersed in an extracellular matrix- blood plasma

Question 51

What are the two types of cells found in nervous tissue?

Answer 51

Neurons, glial cells

Question 52

What is the function of neurons?

Answer 52

Encode information as electrical impulses that travel along their axons

Question 53

What is the function of glial cells?

Answer 53

Supporting functions for neurons

Question 54

What is an organ system?

Answer 54

A group of organs that function together.

Question 55

Organs consist of multiple tissues. Explain how the stomach is a good example.

Answer 55

The stomach wall is arranged in layers. - Epithelial cells - Connective tissue - Smooth muscle - Nervous tissue