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SAT II Biology > Chapter 12 > Flashcards

Chapter 12 Flashcards

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1
Q

2 important functions of the human digestive system

A
  1. breaking down large food molecules into smaller, usable molecules
  2. absorbing these smaller molecules
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2
Q 
What is each one broken down into?
fats
starch
nucleic acids 
proteins
A

glycerol and fatty acids
monosaccharides
nucleotides
amino acids

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3
Q

Vitamins and mineral are small enough to

A

be absorbed without being digested

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4
Q

3 main characteristics of the digestive tract

A
  1. 30 feet long
  2. made of smooth (involuntary) muscle that pushes food along by a process called peristalsis
  3. muscles of the tract are controlled by the autonomic nervous system
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5
Q

What begins at the mouth?

A

mechanical/chemical digestion

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6
Q

What enzyme begins starch digestion? Where is this enzyme?

A

salivary amylase in saliva

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7
Q

What breaks down food mechanically?

A

tongue and differently shaped teeth work together

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8
Q

The type of teeth an animal has is a:

Humans are omnivores and have 3 different types of teeth:

A

reflection of its dietary habits

incisors for cutting, canines for tearing, molars for grinding

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9
Q

What digestion occurs in the esophagus?

A

none

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10
Q

Food in the esophagus is

A

directed away from the windpipe by the epiglottis ( a flap of cartilage in the back of the pharynx, throat)

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11
Q

Esophagus transports food from

A

throat to stomach

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12
Q

Both _____ and ______ digestion occur in the stomach

A

mechanical and chemical

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13
Q

What begins in the stomach?

A

protein digestion

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14
Q

What do the stomach’s thick/muscular walls do?

A

churn food mechanically + secrete gastric juice which contains hydrochloric acid and enzymes that digest proteins

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15
Q

Hydrochloric acid

A
  • begins the breakdown of muscle (meat)

- activates the inactive enzyme pepsinogen to become pepsin, which digests protein

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16
Q

Enzyme ‘rennin’

A

aids in the digestion of the protein in milk

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17
Q

pH of the stomach

A

2-3

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18
Q

What does the cardiac sphincter do? Where is it?

A

located at the top of the stomach

keeps acidified food in the stomach from backing up into the esophagus and burning it

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19
Q

What is the pyloric sphincter?

Where is it?

A

the bottom of the stomach

keeps food in the stomach long enough to be digested

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20
Q

What can excessive acid in the stomach do?

A

can cause an ulcer to form in the esophagus, the stomach, or the duodenum ( the upper intestine)

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21
Q

Common cause of ulcers and treatment

A

bacterium, heliobacter pylori

antibiotics

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22
Q

Small intestine

A

-all digestion is completed and nutrients are absrobed here

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23
Q

2 characteristics of small intestine

A
  • ph is 8

- 6 meters long

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24
Q

All digestion is completed in the

A

duodenum, the first 10 inches of the small intestine

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25
Q

The intestinal enzymes are

A

amylases, proteases, lipases, and nucleases

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26
Q

Pancreatic amylases

A

digest starch

secreted into the small intestine

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27
Q

Peptidases

A
  • ex. trypsin and chymotrypsin

- continue to break down proteins

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28
Q

Nucleases

A

hydrolyze nucleic acids into nucleotides

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29
Q

Lipases

A

break down fats

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30
Q

What lines the small intestine?

A

villi, millions of them, ‘fingerlike’

-absorb all nutrients that were previously released from digested food

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31
Q

Each villus contains

A

capillaries, which absorb amino acids, vitamins, and monosaccharides directly into the bloodstream

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32
Q

Each villus also contains a

A

lacteal, which absorbs fatty acids and glycerol into the lymphatic syste,

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33
Q

Villi have microscopic appendages called

A

microvilli that further enhance the rate of absorption

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34
Q

liver

A

produces bile that converts fats

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35
Q

Bile

A 
pH = 11
neutralizes chyme (acidified food from stomach) entering small intestine
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36
Q

Other functions of the liver include

A
  • breaks down food/recycle RBCs
  • detoxifies blood-removes alcohol and drugs
  • produces cholesterol necessary for structure of cell membranes
  • produces the nitrogenous waste urea from protein metabolism
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37
Q

Remember

Bile is not

A

an enzyme

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38
Q

Gallbladder

A
  • stores bile that is produced in liver
  • bile emulsifies fats in small intestine
  • body can function well without a gallbladder
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39
Q

2 functions of the pancreas

A
  • produces enzymes that break down carbs (amylases), proteins (peptidases), lipids (lipases), and nucleic acids, and secretes them into the small intestine
  • produce sodium bicarbonate
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40
Q

Sodium Bicarbonate

A

a base that neutralizes stomach acid, enabling intestinal enzymes, which require a basic environment, to be effective

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41
Q

Since the pancreas is part of the endocrine system,

A

it produces hormones to control blood sugar levels

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42
Q

Large intestine or colon

A

no digestion occurs here

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43
Q

3 major functions of large intestine or colon

A

egestion
vitamin production
reabsorption of water

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44
Q

Egestion

A

removal of undigested waste

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45
Q

Vitamin production

A

bacteria symbionts living in the colons produce the B vitamins, folic acid, and vitamin K

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46
Q

Reabsorption of water

A

constipation- too much water is reabsorbed from the intestine into body
diarrhea- an inadequate amount of water is absorbed back into body

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46
Q

Reabsorption of water

A

constipation- too much water is reabsorbed from the intestine into body
diarrhea- an inadequate amount of water is absorbed back into body

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47
Q

Rectum

A

egestion- removal of undigested waste

last 7-8 inches of the gastrointestinal tract stores feces until their release through the anus

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47
Q

Rectum

A

egestion- removal of undigested waste

last 7-8 inches of the gastrointestinal tract stores feces until their release through the anus

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48
Q

Air enters the nasal cavity and is

A

moistened, warmed, and filtered

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49
Q

Second, air passes through the larynx and

A

down the trachea and bronchi into the tiniest bronchioles, which end in microscopically tiny air sacs called alveoli

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50
Q

Why do humans have an internal respiratory surface?

A

because respiratory gases are exchanged deep inside the body

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51
Q

The rib cage _______ and forces the _______ to contract and move ________, thus expanding the ____ _______ and decreasing the _______ _________.

A 
expands
diaphragm
downward
chest cavity
internal pressure
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52
Q

Why is air drawn into the lungs by negative pressure?

A

because the internal pressure inside the chest cavity is lower than the air pressure surrounding the body

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53
Q

What is the medulla’s (brain) role in respiration?

A

sets the breathing rhythym by monitoring CO2 levels in blood and by sensing changes in the pH of the blood

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54
Q

Blood pH lower than 7.4 triggers

A

autonomic nerves from the medulla to increase the breathing rate to rid the body of more CO2

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55
Q

The concentration of oxygen in the blood usually has

A

little effect on the breathing control centers

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56
Q

What is oxygen in the blood carried by? What does it combine with?

A

by respiratory pigment hemoglobin

combines loosely with oxygen molecules to form molecule oxyhemoglobin

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57
Q

CO2 is the

A

by-product of cell respiration

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58
Q

CO2 is released from

A

every cell and dissolves in the blood

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59
Q

CO2 is carried in the plasma as part of the

A

reversible blood-buffering carbonic acid-bicarbonate ion system

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60
Q

carbonic acid-bicarbonate ion system

A

maintains blood at a constant pH

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61
Q

human circulation consists of a

A

closed circulatory system with arteries, veins, and capillaries

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62
Q

Vessel: Artery
Function:
Structure:

A

carries blood away from the heart under enormous pressure

walls are made of thick layer of elastic, smooth muscle and can withstand high pressure/contract and expand as needed

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63
Q

Vessel: Vein
Function:
Structure:

A

carries blood back to the heart under very little pressure
-walls don’t contain thick layer of muscle, has valve to help prevent backflow, located within skeletal muscle which propels blood upward and back to heart as the body moves and muscles contract

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63
Q

Vessel: Vein
Function:
Structure:

A

carries blood back to the heart under very little pressure
-walls don’t contain thick layer of muscle, has valve to help prevent backflow, located within skeletal muscle which propels blood upward and back to heart as the body moves and muscles contract

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64
Q

Vessel: Capillary
Function:
Structure:

A

allows for diffusion of nutrients and wastes between cells and blood
-blood travels slowly here to allow time for diffusion of nutrients and wastes

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65
Q

Blood consists of

A

several different cell types suspended in a liquid matrix called plasma

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66
Q

How much blood does the average human body contain?

A

4-6 liters of blood

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67
Q

Blood clotting

A

a complex mechanism that begins with the release of clotting factors from platelets and damaged tissue

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68
Q

Anticlotting factors

A

constantly circulate in the plasma to prevent the formation of a clot or thrombus, which can cause serious damage in the absence of injury

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69
Q

Serum is

A

plasma minus clotting factors

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70
Q

What’s necessary for normal blood clotting?

A

calcium

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71
Q

Component: plasma
Scientific name:
Properties:

A

none
liquid portion of the blood
contains clotting factors, hormones, antibodies, dissolved gases, nutrients, and wastes
90% water

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72
Q

Component: RBCs
Scientific name:
Properties:

A 
erythrocytes 
carry hemoglobin and oxygen
don't have a nucleus
live about 120 days 
formed in the bone marrow and recycled in the liver
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73
Q

Component: White blood cells
Scientific name:
Properties:

A

leukocytes
fight infection
formed in the bone marrow
die fighting infection and are 1 component of pus

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74
Q

Component: Platelets
Scientific name:
Properties:

A

thrombocytes
clot blood
cell fragments that are formed in the bone marrow from megakaryocytes

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75
Q

Heart location and size

Beats about

A

beneath the sternum
size of clenched fist
70 beats per minute and pumps about 5 liters of blood

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76
Q

2 atria

A

receive blood from the cells of the body and 2 ventricles pump blood out of the heart

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77
Q

SA

sinoatrial node

A

sets the timing of the contractions of the heart

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78
Q

Electrical impulses travel through the

A

cardiace and body tissues to the skin

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79
Q

What is the heart’s pacemaker influenced by?

A

nervous system

hormones such as adrenaline and body temperature

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80
Q

Blood pressure is lowest in the

A

veins and highest in the arteries when the ventricle contract

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81
Q

Systolic number (120)

A

is a measurement of the pressure when the ventricle contract

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82
Q

Diastolic (80)

A

a measure of the pressure when the heart relaxes

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83
Q

Pathway of blood

blood enter the heart through the vena cava and continues to the

A
  1. right atrium
  2. right atrioventricular (AV) valve or tricuspid valve
  3. right ventricle
  4. pulmonary semilunar valve
  5. pulmonary artery
  6. lungs
  7. pulmonary vein
  8. left atrium
  9. left atrioventricular (AV) valve or bicuspid valve
  10. left ventricle
  11. aortic semilunar valve
  12. aorta
  13. to all the cells in the body
  14. returns to the heart through the vena cava
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84
Q

Blood circulates through the

A

coronary circulation (heart), renal circulation (kidneys), and the hepatic circulation (liver)

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85
Q

Pulmonary circulation

A

includes pulmonary artery, lungs, and the pulmonary vein

86
Q

The pulmonary artery is the only artery that carries

A

deoxygenated blood and the pulmonary vein is the only vein that carries oxygenated blood

87
Q

What are the 2 major regulatory systems that release chemicals?

A

endocrine and nervous system

88
Q

Endocrine system secretes

Nervous system secretes

A

hormones

neurotransmitters

89
Q

Epinephrine functions boths as the

A

fight or flight hormone secreted by the adrenal gland

neurotransmitter that sends a message from one neuron to another

90
Q

Hormones are produced in

A

ductless (endocrine) glands and move through the blood to a specific target cell , tissue, or organ that can be far from the original endocrine gland

91
Q

Hormones can either be

A

immediate short lived responses or

dramatic long-term development of an entire organism

92
Q

Tropic hormones

A

hormones that stimulate other glands to release hormones and can have a far-reaching effect

93
Q

Example of tropic hormones

A

TSH- thyroid stimulating hormone

anterior pituitary region in the brain stimulates the thyroid to release thyroxin

93
Q

Pheromones

A

in the urine of a dog carry a message between different individuals of the same species

94
Q

Hypothalamus

A

bridge between the endocrine and nervous system

95
Q

Hypothalamus as a part of the nervous system

A

sends electrical signals to the adrenal gland to release adrenaline

96
Q

Hypothalamus as a part of the endocrine gland

A

produces oxytocin and antidiuretic hormone that it stores in the posterior pituitary

97
Q

Hypothalamus also contains the body’s

A

thermostat and centers for regulating hunger and thirst

98
Q

Anterior pituitary gland

examples of hormones

A 
growth hormone GH
luteinizing hormone LH 
thyroid-stimulating hormone TSH
adrenocorticotropic hormone ACTH
follicle-stimulating hormone FSH
99
Q

Anterior pituitary functions

A

stimulates growth of bones
stimulates ovaries and testes
stimulates thyroid gland
stimulates adrenal cortex to secrete glucocorticoids
stimulates gonads to produce sperm and ova

100
Q

Posterior pituitary hormones

A

oxytocin

antidiuretic hormone ADH

101
Q

Posterior pituitary functions

A

stimulates contractions of uterus and mammary glands

promotes retention of water by kidneys

102
Q

Thyroid Hormones

A

thyroxin

calcitonin

103
Q

Thyroid functions

A

controls metabolic rate

lowers blood calcium levels

104
Q

Parathyroid Hormone

A

parathormone

105
Q

Parathyroid functions

A

raises blood calcium levels

106
Q

Adrenal cortex hormone

A

glucocorticoids

107
Q

Adrenal cortex function

A

raises blood sugar levels

108
Q

Adrenal medulla hormones

A

epinephrine (adreline)

nonepinephrine (noradrenaline)

109
Q

Adrenal medulla function

A

raises blood sugar level by increasing rate of glycogen breakdown by liver

110
Q

Pancreas-islets of Langerhans hormones

A

insulin

glucagon

111
Q

Pancreas- isets of Langerhans functions

A

lowers blood glucose levels

raises blood glucose levels

112
Q

Thymus (in neck) hormone

A

thymosin

113
Q

Thymus (in neck) function

A

stimulates T lymphocytes as part of the immune response

114
Q

Pineal (in brain) hormone

A

melatonin

115
Q

Pineal (in brain) function

A

involved in biorhythms

116
Q

Ovaries hormones

A

estrogen

progesterone

117
Q

Ovaries function

A

stimulates uterine lining, promotes development and maintenance of primary and secondary characteristics of females
promotes uterine lining growth

118
Q

Testes Hormones

A

androgens

119
Q

Testes functions

A

support sperm production and promote secondary sex characteristics

120
Q

2 types of hormones

A

steroid
nonsteroidal or polypeptide hormones
-each stimulate target cells in different ways

121
Q

Lipids or Steroid hormones

A
  • diffuse directly through the plasma membrane

- bind to a receptor inside the cell that triggers the cell’s response

122
Q

Protein or polypeptide hormones (nonsteroidal)

A

-cannot dissolve in the plasma membrane so they bind to a receptor on the surface of the cell

123
Q

In nonsteroidal hormones, the hormone (the first messenger) binds to a

A

receptor on the surface of the cell, it triggers a secondary messenger such as c-AMP, which converts the extracellular chemical signal to a specific response inside the cell

124
Q

Feedback mechanism

A

a self-regulating mechanism that increases or decreases an action or the level of a particular substance

125
Q

Positive feedback

A

enhances an already existing response

126
Q

Example of positive feedback

A

during childbirth, the pressure of the baby’s head against sensors near the opening of the uterus stimulates more uterine contractions which causes increased pressure against the uterine opening, which causes more contractions
-this positive feedback loop brings labor to an end and the birth of a baby

127
Q

Negative feedback

A

a common mechanism in the endocrine system (and elsewhere) that maintains homeostasis

128
Q

Example of negative feedback

A

when the thyroxin in the blood is too low, the hypothalamus stimulates the anterior pituitary to release a hormone, thryoid-stimulating hormone (TSH), which stimulates the thyroid to release more thyroxin
-when the level of thyroxin is adequate, the hypothalamus stops stimulating the pituitary

129
Q

The vertebrate nervous system consists of

A

central and peripheral components

130
Q

The central nervous system (CNS) consists of

A

the brain and spinal cord

131
Q

The peripheral nervous system (PNS) consists of

A

all nerves outside the CNS

132
Q

Peripheral nervous system is further divided into

A

sensory- conveys information from sensory receptors or nerve endings
motor- stimulates voluntary and involuntary muscles and consists of two more systems

133
Q

Motor system is further divided into

A

somatic- controls voluntary muscles

autonomic- controls involuntary muscles

134
Q

Sympathetic

A
  • fight or flight response
  • increases heart and breathing rate
  • liver converts glycogen to glucose
  • bronchi of lungs dilate and increase gas exchange
  • adrenaline raises blood glucose levels
135
Q

Parasympathetic

A
  • opposes the sympathetic system
  • calms the body
  • decreases heart/breathing rate
  • enhances digestion
136
Q

Neuron

A

basic functional unit of the nervous system
-consists of a cell body which contains nucleus and other organelles and 2 types of cytoplasmic extensions called dendrites and axons

137
Q

Dendrites

A

sensory
receive incoming messages from other cells and carry the electrical signal to the cell body
-neurons can having 100s of dendrites

138
Q

Axons

A

transmit an impulse from the cell body outward to another cell
-neuron can only 1 axon which can be several feet long in large mammals

139
Q

Most axons are wrapped in a

A

myelin sheet that protects the axon and speeds the impulse

140
Q

What’s the simplest nerve response?

A

a reflex arc

141
Q

Reflex arc is

A

inborn, automatic, and protective

142
Q

Example of a reflex arc

A

knee-jerk reflex- consists of only a sensory and a motor neuron
-the impulse moves from the sensory neuron in your knee to the motor neuron that directs the thigh muscle to contract, spinal cord is not involved in this type of reflex

143
Q

A more complex reflex arc consists of 3 neurons:

A

sensory, motor, and an interneuron or association neuron

144
Q

Explain a complex reflex arc

A

a sensory neuron transmits an impulse to the interneuron in the spinal cord which sends 1 impulse to the brain for processing and also one to the motor neuron to effect change immediately (at the muscle)

145
Q

All living cells exhibit a membrane potential

A

a difference in electrical charge between the cytoplasm (negative charge) and extracellular fluid (positive charge)

146
Q

How do physiologists measure membrane potential?

A

its between -500 mV to -100 mV

-the negative sign indicates that the inside of the cell is negative relative to the outside of the cell

147
Q

Resting Potential

A neuron at rest or unstimulated (resting potential)

A

is polarized and has a membrane potential of about -70 mV

148
Q

How did the sodium-potassium pump maintain this polarization?

A

by actively pumping ions out of the cell that leak inward

149
Q

In order for the nerve to fire, a stimulus must be

A

strong enough to overcome the resting threshold or resting potential

150
Q

The larger the membrane potential, the

A

stronger the stimulus must be to cause the nerve to fire

151
Q

Action potential or impulse

A

can only be generated in the axon of a neuron

152
Q

When an axon is stimulated sufficiently to overcome the threshold,

A

the permeability of a region of the membrane suddenly changes

153
Q

Sodium channels open and sodium

A

floods into the cell, down the concentration gradient

in response, potassium channels open and potassium floods out of the cell

154
Q

This rapid movement of ions or wave of depolarization

A

reverses the polarity of the membrane is called an action potential
-the action potential is localized and last a very short time

155
Q

The sodium potassium pump restores the membrane to its

A

original polarized condition by pumping sodium and potassium ions back to their original positions

156
Q

The period of repolarization when the sodium potassium pump restores the membrane, which lasts a

A

few milliseconds, is called the refractory period, during which the neuron can’t respond to another stimulus

157
Q

The refractory period ensures that an

A

impulse moves along an axon in one direction only since the impulse can move only to a region where the membrane is polarized

158
Q

The first action potential generates a second action potential which

A

generates a third, and so on

159
Q

The impulse moves along the axon

A

propagating itself without losing any strength

-if the axon is myelinated, the impulse travels faster

160
Q

The action potential is ‘all or nothing’

A

either the stimulus is strong enough to cause an action potential or it’s not

161
Q

How does the body distinguish between a strong and weak stimulus?

A

by the frequency of action potentials

-a strong stimulus sets up more action potentials than a weak one does

162
Q

An impulse travels along an axon ______, it crosses a synapses ________.

A

electrically, chemically

163
Q

The cytoplasm at the terminal branch of the neuron

A

contains many vesicles, each containing 100s of molecules of neurotransmitter

164
Q

Depolarization of the presynaptic membrane causes

A

Ca++ ions to rush into the terminal branch through calcium-gated channels

165
Q

What does the sudden rise in Ca++ levels do to vesicles?

A

stimulates the vesicles to fuse with the presynaptic membrane and release the neurotransmitter by exocytosis into the synapses, which sets up another action potential on the adjacent cell

166
Q

What happens after a neurotransmitter released into a synapse?

A

destroyed by an enzyme that stops the impulse at that point

167
Q

What are the most common neurotransmitters?

A

acetylcholine, serotonin, epinephrine, norepinephrine, dopamine, and GABA

168
Q

Many cells release the gas _____ to stimulate other cells

A

NO nitric oxide

169
Q

Eye

cones

A

photoreceptors in the retina that distinguish different colors

170
Q

Eye

cornea

A

tough, clear covering that protects the eye and allows light to pass through

171
Q

Eye

humor

A

fluids that maintain the shape of the eyeball

172
Q

Eye

iris

A

colored part of the eye that controls how much light enter the eye

173
Q

Eye

lens

A

focuses light onto the retina

174
Q

Eye

pupil

A

small opening in the middle of the iris

175
Q

Eye

retina

A

converts light into nerve impulses that are carried to the brain

176
Q

Eye

rods

A

photoreceptors in the retina that are extremely sensitive but don’t distinguish different colors

177
Q

Ear

auditory canal

A

ear canal, where sound enters

178
Q

Ear

cochlea

A

fluid-filled part of inner ear, sends nerve impulses to brain

179
Q

Ear

ear bones

A

hammer, anvil, and stirrup;

transmit vibrations from eardrum to oval window

180
Q

Ear

eustachian tube

A

equalizes pressure between environment and inner ear

181
Q

Ear

oval window

A

sends waves of pressure to the cochlea

182
Q

Ear

Semicircular canals

A

fluid filled, helps you maintain your balance

183
Q

Ear

tympanum

A

ear drum, vibrates as sound waves hit it

184
Q

Excretion removes

A

CO2 and water from cell respiration and nitrogenous wastes from protein metabolism

185
Q

Organs of excretion

A

skin, lungs, liver, and kidneys

186
Q

Skin excretes

A

sweat consisting of water and salts, including urea

187
Q

Lungs excrete

A

water vapor and CO2 from the Krebs cycle

188
Q

Liver doesn’t excrete

A

any substances from the body but its the site of deamination of amino acids and the production of urea

189
Q

Kidneys excrete

A

excess water and urea

190
Q

Kidney adjusts both the

A

volume and the concentration of urine depending on the animal’s intake of water and salt and the production of urea

191
Q

the kidneys are supplied by blood from

A

renal artery

192
Q

The kidneys filter about

A

1,500 liters of blood per day and produce on average 1.5 liters of urine

193
Q

Why is the kidney able to respond quickly to the changing requirements of the body?

A

its under hormonal control

194
Q

A major hormone, ADH _______, is released by the

A

antidiuretic hormone

posterior pituitary and targets the collecting tube of the nephron

195
Q

ADH regulates

A

blood pressure by controlling how much water is reabsorbed by the kidneys

196
Q

Nephron

A

basic functional unit of the kidney
consists of a cluster of capillaries known as the glomerulus-which sits inside a cuplike structure called Bowman’s capsule, a long narrow tube called the tubule, and the loop of Henle

197
Q

Each human kidney contains about

A

1 million nephrons

198
Q

The nephron carries out its job in 4 steps

A

filtration
secretion
reabsorption
excretion

199
Q

Filtration in the kidney occurs by

A

diffusion

it’s passive and non-selective

200
Q

The filtrate contains everything small enough to

A

diffuse out of the glomerulus and into Bowman’s capsule including glucose, salts, vitamins, wastes such as urea, and other small molecules

201
Q

From the bowman’s capsule, the filtrate travels into the

A

loop of Henle and then the collecting duct or tubule

202
Q

From the collecting tubule, the filtrate trickles into the

A

ureter and the urinary bladder for temporary storage and then to the urethra and out of the body

203
Q

Secretion is the

A

active, selective uptake of molecules that didn’t get filtered into Bowman’s capsule
-this occurs in the tubules of the nephron

204
Q

Reabsorption is the process by which most of the

A

water and solutes (glucose, amino acids, and vitamins) that initially entered the tubule during filtration are transported back into the capillaries and thus back to the body

205
Q

Where does reabsorption occur?

A

in the tubule, the loop of Henle, and the collecting tubule

-the longer the loop of henle, the greater the reabsorption of water

206
Q

Everything that passes into the collecting tubule

A

is excreted from the body

207
Q

The 3 types of muscle are

A

smooth
cardiac
skeletal

208
Q

Smooth or involuntary muscle

A
  • makes up the walls of blood vessels and the digestive tract
  • doesn’t have a striated appearance
  • under the control of the autonomic nervous system
209
Q

Skeletal or voluntary (striated) muscles

A
  • very large and multinucleate
  • work in pairs, 1 muscle contracts while the other relaxes
  • biceps and triceps are one pair
210
Q

Cardiac muscle

A
  • found in the heart and is striated like skeletal muscle
  • generates its own action potential
  • individual heart cells will beat on their own, even when removed from the body
211
Q

Within the cytoplasm of each skeletal muscle cell

A

are 1000s of fibers called myofibrils that run parallel to the length of the cell

212
Q

Myofibrils consist of

A

thick and thin filaments

213
Q

Each thin filament consists of

A

actin proteins

214
Q

Each thick filament is composed of

A

myosin proteins

215
Q

How do muscles contract?

A

when thick and thin filaments slide over each other

SAT II Biology (15 decks)

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