Unit 14 - Coordination and response Flashcards
1
Q
Stimulus
A
A change in environment that can be detected by an organism
2
Q
Nervous system
A
Organ system that allows humans and other animals to detect stimuli and respond to them - coordinates and regulars the body’s functions
3
Q
CNS
A
- Central nervous system - brain and spinal cord
- Coordinates all reactions and nervous communication around the body
4
Q
PNS
A
- Peripheral nervous system - nerves in any other parts
- transmits impulses from the CNS to all parts of the body
5
Q
Three main types of neurons
A
- Sensory neurons
- Relay neurons
- Motor neurons
6
Q
Sensory neurons
A
- Transfer nerve impulses away from the receptor cells when stimulus is detected
- Can be long to transmit impulses to distant parts of the body near the spinal cord
7
Q
Relay neurons
A
- Connect one neuron to the next
- Does not need to be long
- Found in the brain or between sensory & motor neurons in the spinal cord
8
Q
Motor neurons
A
- Transfer nerve impulses from the brain or spinal cord to effectors e.g. muscles or gland
- Can be long because they need to transfer impulses from spinal cord to distant parts of the body
9
Q
Synapse structure
A
The junction between two neurons
10
Q
Synapse Function
A
Allows impulse to travel from an axon terminal of one neuron to a dendrite in another neuron
11
Q
Vesicle Structure
A
Tiny, bubble-like structures in axon terminals that contain neurotransmitters
12
Q
Dendrites
A
Have receptor molecules that can bind with neurotransmitters
13
Q
Process of nerve impulse
A
1.Vesicles release neurotransmitters into the synaptic cleft
2.Neurotransmitters travel across the gap by diffusion
3.Neurotransmitters bind with receptor molecules on the dendrite neuron
4.Nerve impulse is triggered in this neuron
14
Q
Features of reflex actions
A
- Automatic
- Rapid
- Innate
15
Q
Reflex arc
A
The pathway through the body that blinds about a reflex action
16
Q
Path of a reflex arc
A
Receptor –> sensory neuron –> relay neuron –> motor neuron –> effector
17
Q
Receptors
A
Cells that can detect different stimuli
18
Q
Types of receptors
A
- Touch receptors - skin
- Sound receptors - ear
- Light receptors - eye
- Chemical receptors - nose, tongue, mouth
- Temperature receptors - skin, brain
19
Q
Effector
A
Produces a response e.g. a muscle or gland
20
Q
Sense organ
A
Group of receptor cells that respond to a specific stimulus
21
Q
Eye; conjunctiva structure
A
Mucous membrane that covers the front of the eye and lines the inside of the eyelid
22
Q
Eye; conjunctiva function
A
Provides the eye with moisture so that it can open and close easily
23
Q
Eye; cornea structure
A
Front part of the sclera, tough, convex and transparent
24
Q
Eye; cornea function
A
- Refracts the light as it enters the eye
- It helps to protect the eye
25
Eye; pupil structure
The opening in the middle of the eye that appears to be black
26
Eye; pupil function
Allows light to enter the eye and focus on the retina
27
Eye; lens structure
Soft, flexible, transparent, bi-concave disc
28
Eye; lens function
Focuses light on the retina
29
Eye; iris structure
The colored part of the eye
30
Eye; iris function
Contains muscles that control the size of the pupil and how much light can enter
31
Eye; suspensory ligament structure
A group of fibers that connects the lens to the ciliary muscles
32
Eye; suspensory ligament function
Holds the lens in place
33
Eye; ciliary muscles structure
Circular ring of muscle surrounding the lens
34
Eye; ciliary muscles function
Causes the lens to change shape as it contracts and relaxes
35
Eye; sclera structure
Tough, white outer part of the eye that extends from the cornea to the back of the eye
36
Eye; sclera function
Protects the eye from serious damage and provides a good surface for the muscles that control eye movement to connect to
37
Eye; retina structure
A thin lining on the back of the eye
38
Eye; retina function
Contains cells called rods and cones which are sensitive to light
39
Eye; vitreous humor structure
Clear gel like substance located between the retina and the lens
40
Eye; vitreous humor function
Keeps the eye firm and gives it shape
41
Eye; blind spot structure
The area of the eye where the optic nerve and the retina meet
42
Eye; blind spot function
Not sensitive to light as it contains no rod or cone cells
43
Eye; optic nerve structure
Group of sensory neurons at the back of the eye
44
Eye; optic nerve function
Sends visual information to the brain
45
Pupil reflex in dim light
- Pupil dilates
- More light let in
- Radial muscles contract
- Circular muscles relax
46
Pupil reflex in bright light
- Pupil constricts
- Less light let in
- Radial muscles relax
- Circular muscles contract
47
Antagonistic pair of muscles in the iris
The radial muscles and circular muscles
48
Accommodation
The focusing of light, through the changing of the shape of the lens, onto the retina
49
Accommodation with distant objects
- Ciliary muscles relax
- Tension in suspensory ligaments increases
- Lens becomes thinner
- Light is refracted less strongly
50
Accommodation with nearby objects
- Ciliary muscles contract
- Tension in the suspensory ligaments decreases
- Lens becomes thicker
- Light is refracted more strongly
51
Two types of receptors in the retina
Rods and cones
52
Fovea
- Part of the retina
- Where the sharpest image is produced
- Light is focused on the fovea
53
Cones
- Located in the fovea
- Provide color vision
- Detect red, green or blue light
54
Rods
- More sensitive to light than cones
- Allow vision in dim light
- At the sides of the retina
- Only detect in black and white and detect light intensity
55
Endocrine system
The series of glands to make hormones
55
Hormone
A chemical substance produced by a gland that is carried to the blood to alter the activity of one or more specific organs
56
Target organ
The organ affected by a particular hormone
57
Endocrine glands
Adrenal gland, pancreas, ovary, testis
58
Hormone produced in adrenal gland
Adrenaline
59
Hormone produced in pancreas
Insulin glucagon
60
Hormone produced in ovary
Estrogen
61
Hormone produced in testis
Testosterone
62
Insulin function
Causes cells in the liver to remove glucose from the blood and store it as glycogen
63
Glucagon
Stimulates breakdown of stored glycogen, releasing more glucose into the blood
64
Estrogen
- Female sex hormone
- Controls development of reproductive system and sexual characteristics
65
Testosterone
- Male sex hormone
- Controls development of reproductive system and sexual characteristics
66
Effects of adrenaline
- Pupils dilate - let more light in
- Breathing rate increases - more oxygen added to the blood and more carbon dioxide removed, cells respire quicker
- Pulse rate increases - muscles receive more blood containing glucose
-Liver cells convert glycogen to glucose - more glucose available for respiration in muscle cells
67
Homeostasis
The maintenance of a constant internal environment in the body
68
Factors of homeostasis
- Body temperature
- Concentration of glucose in the blood
- Water levels
69
Negative feedback
The mechanism that controls homeostasis by reversing changes in the environment
70
Needed mechanisms for homeostasis
- Receptor cells - to detect stimulus
- Coordination center e.g. brain
- Effectors - Glands or muscles to respond
71
Thermoregulation
Maintaining a constant internal temperature in the body
72
Structure of the skin
Hair, Sweat gland, Hair erector muscle, Receptor, Blood vessels, Sensory nerve, Fatty tissue
73
Body mechanism to cool
Sweating
74
Body mechanism to heat up
Shivering
75
Shivering
- Muscles contracting and relaxing in an uncontrollable and uncoordinated way
- Uses energy from respiration which also heats
76
Sweating
- Watery mixture secreted onto the surface of the skin
- Evaporation of sweat has a cooling effect
77
Hypothalamus
Part of the brain that controls the thermoregulatory system and changes and control body temperature
78
Vasoconstriction
- Arterioles narrow
- Reduces blood flow
- Decreases rate of energy transfer
- Keeps warm
78
Vasodilation
- Arterioles widen
- Lets more blood flow near the surface of the skin
- Increases energy transfer to surroundings
- Cools down
79
Pancreas
- Monitors levels of glucose concentration in blood
- Secretes insulin when there is high amounts of glucose
80
Type 1 diabetes
Develops when somebody can't control their concentration of glucose in the blood - Pancreas doesn't produce insulin
81
Symptoms of Type 1 diabetes
- Frequent urination - trying to excrete excess glucose
- Increased thirst - resulting from frequent urination and need to dilute blood
82
Tropism
Response by a plant to a stimulus
83
Gravitropism
Response where parts of a plant grow towards or away from gravity
84
Phototropism
Response where parts of a plant grow towards or away from the direction where light is coming
85
Positive tropism
Plant moves towards the stimulus
86
Negative tropism
Plant moves away from the stimulus
87
Plant hormone that causes tropisms
Auxin
88
Auxin distribution
- Equal along the shoot if source of light is directly overhead
- Unequally in response to gravity or light - some cells elongate more
