Chapter 12 - Coordination And Response Flashcards
1
Q
What does the endocrine system consist of?
A
Hormones and glands
2
Q
What does the nervous system consist of?
A
Nerves and brain
3
Q
Name the 2 parts that the nervous system is divided into:
A
Central nervous system
Peripheral nervous system
4
Q
What does the central nervous system consist of?
A
1) Brain
2) Spinal cord
5
Q
What does the peripheral nervous system include?
A
All the nerves that connect the rest of the body to the central nervous system
6
Q
What is the difference between a neurone and nerve?
A
A single nerve cell is called a neurone. Neurones are Clustered together to form a large nerve fibre.
7
Q
Name 4 components that make coordination possible:
A
1) sense organs
2) sensory impulses
3) motor impulses
4) effectors
8
Q
What are the 3 classifications of neurones?
A
1) sensory neurones
2) relay neurones
3) motor neurones
9
Q
Where are sensory neurones found?
A
Connected to sense organs
10
Q
Where are relay neurones found?
A
Found in CNS
11
Q
Where are motor neurones found?
A
Connected to the effectors
12
Q
What is another name for motor neurones?
A
Effector neurones
13
Q
What do sensory neurones do?
A
They carry messages from a sense organ to the CNS.
14
Q
What do relay neurones do?
A
Connect neurones to one another.
15
Q
What do motor neurones do?
A
They transmit messages from the CNS to the effectors.
16
Q
Name the 3 basic structures of a neurone:
A
1) cell body - contains the nucleus and a little cytoplasm
2) dendrites - branching fibres that extend from the cell body
3) nerve fibre(s) - filaments) of cytoplasm that is surrounded by an electrical insulating sheath. These fibres extend out of the main cell body and transmit electrical impulses.
17
Q
Define stimuli:
A
Changes in the environment that can be detected by organisms.
18
Q
Define receptors:
A
Cells/groups of cells that detect stimuli.
19
Q
Define effectors:
A
Parts of the body that respond to a stimulus
Eg. Muscles and Glands
20
Q
Define coordination:
A
Ensuring that the actions of different parts of the body work together.
21
Q
Define nerve:
A
A group of neurone axons lying together
(Like an electrical cable containing many wires)
22
Q
Define a neurone:
A
A cell that is specialised for conducting electrical impulses rapidly.
23
Q
Define a motor neurone:
A
A neurone that transmits electrical impulses from the CNS to an effector.
24
Q
Define axon:
A
A long, thin fibre of cytoplasm that extends from the cell body of a neurone.
25
Define dendrites:
**Short** fibres of **cytoplasm** in a neurone.
26
Define nerve impulses:
An electrical **signal** that **passes** rapidly along an **axon**.
27
What are the 2 methods that **receptors**use to send information to the **effectors**?
1) Nerves (nervous system) - fastest way
2) Hormones (endocrine system) - slower way
28
What are the cells that make up the nervous system?
Neurones
29
What is the structure of a neurone that enables it to transmit electrical signals very quickly?
Long, thin fibres of cytoplasm stretching out from the cell body.
(Shorter ones - dendrites)
(Longer ones - axons)
30
Briefly explain how electrical impulses move through a **motor neurone**?
1) The **dendrites** pick up electrical signals from nearby neurones
2) The signal passes to the **cell body**
3) The nerve impulses then pass along the **axon** (which might pass it to another neurone)
31
What **myelin**?
A layer of **fat** and **protein** around some of the nerve fibres in mammals.
32
What is the function of **myelin**?
It **insulates** the nerve fibres → there are narrow gaps in the myelin sheath → carry impulses a lot **faster**
Eg. In a cat, a myelinated nerve fibre carries impulses at up to 100m per second.
Whereas without myelin, it can only carry impulses at about 5m per second.
33
What is the role of the CNS?
To coordinate the electrical impulses traveling through the nervous system.
34
What is the CNS made up of?
Neurones
35
What is the PNS made up of?
1) Made up of nerves that spread out of the CNS
The nerves are made up of 100s of neurones.
2) Also includes the receptors in our sense organs.
36
What happens when a receptor detects a stimulus?
The receptor sends an electrical impulse along a neurone to the brain/spinal cord.
The brain/spinal cord then receives the impulse and sends it on along the **appropriate nerve fibres* to the **appropriate effector**.
37
What is a reflex arc?
A **series of neurones** (sensory, relay and motor) that **transmit electrical impulses** from a **receptor** to an **effector**.
38
What is a reflex action?
A means of automatically and rapidly integrating and coordinating stimuli with the responses of effectors.
39
Define Central Nervous System:
The brain and spinal cord.
40
Define Peripheral Nervous System:
The nerves outside the brain and spinal cord.
41
Define sensory neurone:
A neurone that transmits electrical impulses **from a receptor** to the CNS.
42
Define relay neurone:
A neurone that transmits electrical impulses **within** the CNS.
43
Why are reflex actions useful:
You don’t waste time thinking what to do. Reflex actions are automatic.
44
What happens when you receive more than one stimulus at once?
These stimuli will be combined to produce electrical impulses in **sensory neurones**.
These will travel fast around the reflex arc and produce an appropriate and fast response.
45
Define a **synapse**:
A junction between two neurones.
46
Define **synaptic gap**:
A tiny gap between 2 neurones, at a synapse.
47
Define vesicle:
Very small vacuole.
48
Define **neurotransmitter**:
A chemical stored in vesicles at the end of neurones, which can be released to diffuse across the synaptic gap and set up an electrical impulse in the next neurone.
49
Define receptor proteins:
Proteins on the membrane of the **second** neurone at a **synapse**, which have a complementary shape to the molecules of neurotransmitter.
50
What is part of the synapse?
1) The ends of the 2 neurones on either side of the synaptic gap
2) The synaptic gap itself
51
How does the neurotransmitter move across the synaptic gap?
By diffusion
52
Why do the molecules of neurotransmitter attach to receptor proteins?
Because the shape of the neurotransmitter is complementary to the shape of the receptor proteins.
53
What is the function of synapses?
They ensure that nerve impulses only travel in **one** direction.
54
Define sense organ:
A group of receptor cells that are able to respond to a specific stimulus.
55
Define retina:
A **tissue** at the **back of the eye** that **contains receptor cells** that respond to **light**.
56
Define optic nerve:
The **nerve** that carries electrical impulses from the retina **to** the brain.
57
Define blind spot:
The **part of the retina** where the *optic nerve leaves*, and where there are **no receptor cells**.
58
Define **fovea**:
The part of the retina where cone cells are very tightly packed.
This is where light is focussed when you look directly at an object.
59
Define cones:
**Receptor cells** in the retina that are sensitive to light of **different colours** but only function in bright light.
60
Define rods:
**Receptor cells** in the retina that respond to **dim light**, but do not detect colour.
61
Define iris:
The coloured part of the eye
Contains muscles that can alter the size of the pupil
62
Define pupil:
A circular gap in the middle of the iris, through which light can pass.
63
Define iris reflex (pupil reflex):
An automatic response to a change in light intensity
The receptors → in the retina
The effector → the muscles in the iris
64
Define antagonistic muscles:
A pair of muscles whose contraction has opposite effects
When one contracts → other relaxes
65
Define refraction:
Bending light rays
66
Define cornea:
A transparent layer near the front of the eye, which refracts light rays entering the eye.
67
Define lens:
A transparent structure in the eye, which changes shape to focus light rays onto the retina.
68
Define accommodation:
Changing the shape of the lens to focus on objects at different distances from the eye.
69
Define suspensory ligaments:
Strong, inelastic fibres that hold the lens in position
When under tension, they pull the lens into a thinner shape
70
Define ciliary muscle:
A circle of muscle surrounding the lens,and joined to it by the suspensory ligaments
When it contracts, it slackens the ligaments so that the lens becomes fatter
71
What is the function of the bony socket in your skull?
Holds and protects the eye
72
What is the function of the liquid filling the eye?
Helps keep it in shape
73
What is the conjunctiva?
A thin, transparent membrane that covers the front of the eye
74
What is the function of the conjunctiva?
Helps protect the parts behind it
75
What is conjunctivitis?
When the membrane (conjunctiva) becomes sore and inflamed
76
What is the function of the tear glands?
They make a fluid that keeps the surface of your eye moist.
77
What is the structure and function of the fluid created by your tear glands?
Fluid contains enzyme, **lysozyme** which can kill bacteria
78
What is the function of your eyelids?
They wash the fluid created by tear glands across your eye when you blink
79
What is the function of your eyebrows, eyelashes and eyelids?
They keep dirt from landing on the surface of your eyes
80
True or false: The closer the receptor cells are together, the blurrier the image the brain creates.
False.
True statement: The closer the receptor cells are together, the clearer the image the brain can create.
81
What are the 3 types of cones that you get?
1) Red sensing cones (cones sensitive to red light)
2) Blue sensing cones
3) Green sensing cones
82
What colours do rods allow us to see?
Only black and white
83
What is the structure of cones and rods on the retina?
The cones are tightly packed together while the rods are further out on the retina and less tightly packed
84
What image do cones produce?
Sharp image in colour
85
What image do rods produce?
Less detailed image
86
What is the structure and function of the iris?
The iris is colourful, it contains **pigment** that absorbs light and stops it from passing through
87
What happens to the pupil in high light intensity?
The iris closes in, and makes the pupil small
88
Why does the pupil get smaller in high light intensity?
It stops too much light getting in and damaging the retina
89
What happens to the pupil in low light intensity?
The iris pulls back from the pupil, making the pupil larger
90
How is the iris able to adjust the size of the pupil? (Refer to the muscles in the eye)
The iris contains muscles
1) There are **circular muscles** arranged in circles around the pupil → when they contract → pupil gets smaller
2) **Radial** muscles run outwards from the edge of the pupil → when they contract → makes the pupil dilate
91
Why must refraction occur when light shines into the ey?
It must happen so that the light rays can be focussed exactly onto the retina for a clear image
92
What structure in the eye is responsible for refraction?
Most of it is done by the **cornea**
The **lens** makes fine adjustments
93
How much must light rays be bent when entering the eye for the following:
1) Distant object
2) Nearby object
1) Only need to be refracted **slightly** by the *thin lens*
Because: the distant object’s light rays are only diverging slightly
2) Need to be refracted inwards quite strongly by the *thick lens*
Because: the nearby object’s light rays are diverging greatly
(Both are mostly refracted by the cornea)
94
Explain how the thickness of the lens affects the bending of light rays:
Thicker the lens → the more it bends light rays
Thinner the lens → less it bends light rays
95
What holds the lens in position?
Suspensory ligaments
96
What changes the tension on the suspensory ligaments, and thus the shape of the lens?
Ciliary muscle
97
Explain what happens to the suspensory ligaments and the lens when the ciliary muscle contracts and relaxes:
Ciliary muscle *contracts* **→** Suspensory ligaments *loosen* **→** lens gets *thicker*
Ciliary muscle *relaxes* **→** Suspensory ligaments *tighten* **→** lens is pulled thin
98
Define hormones:
**Chemicals** that are produced by a gland and carried in the blood, which **alter the activities** of their specific target organs
99
Define endocrine glands:
Glands that secrete hormones
100
Define target organs:
Organs that’s activity is altered by hormones
101
Define adrenaline:
A hormone secreted by the adrenal glands, which prepares the body for fight/flight
102
Define tropisms:
A **growth response** by a plant, in which the **direction of growth** is *related* to the **direction of the stimulus**.
103
Define phototropism:
A response in which part of a plant grows towards/away from the direction from which the light is coming
104
Define gravitropism:
A response in which part of a plant grows towards/away from gravity
105
How are hormones carried through the body?
Passed from the glands into the blood and carried around the body in the blood plasma
106
What hormone does the adrenal gland secrete?
Adrenaline
107
What is the function of adrenaline?
Prepares body for vigorous activity
108
What endocrine gland secretes the hormones, **insulin** and **glucagon**?
The pancreas
109
What is the function of the hormone insulin?
Reduces the concentration of glucose in the blood
110
What is the function of the hormone **glucagon**?
Increases the concentration of glucose in the blood
111
What hormone does the endocrine gland, **testis** secrete?
Testosterone
112
What is the function of the hormone testosterone?
Causes the development of male secondary sexual characteristics
113
What endocrine gland secretes the hormone, oestrogen?
Ovary
114
What is the function of the hormone oestrogen?
Causes the development of female secondary sexual characteristics, and helps in the control of the menstrual cycle
115
How many adrenal glands are there?
2
116
Where are the 2 adrenal glands situated?
One above each kidney
117
Name 2 examples of how adrenaline aids the fight or flight response:
1) Your heart beats faster supplying your muscles with more oxygen for aerobic respiration so that your muscles have more energy and you can run away faster
2) Widens your pupils so that you can see the danger more clearly
118
Compare the **nervous** and **endocrine** system with 5 differences:
*Difference 1*
**N)** Made up of neurones
**E)** Made up of glands
*Difference 2*
**N)** Information transmitted in the form of electrical impulses
**E)** Information transmitted in the form of chemicals (hormones)
*Difference 3*
**N)** Impulses transmitted along neurones
**E)** Chemicals carried in blood plasma
*Difference 4*
**N)** Impulses travel very quickly, action is fast
**E)** Chemicals travel more slowly, so action is slower
*Difference 5*
**N)** Effect of a nerve impulse usually only lasts for a very short time
**E)** Effect of a hormone may last longer
119
What effect does adrenaline have on the liver?
It causes the liver to release **glucose** into the blood
Because this along with the extra oxygen (from the increased heart and breathing rate) allows muscles to increase their metabolic activity
120
What is a negative response when referring to tropisms (growth response)?
Growth away from a stimulus
121
What is a positive response when referring to tropisms (growth response)?
Growth towards a stimulus
122
What are two important stimuli for plants?
Light and gravity
123
Are shoots positively or negatively gravitropic?
Negatively gravitropic, because they grow away from the pull of gravity
124
Are roots negatively or positively gravitropic?
Positively gravitropic, because they grow towards the pull of gravity
125
Are shoots negatively or positively phototropic?
Positively phototropic, because they generally grow towards light
126
Why do shoots and flowers grow upwards?
Shoots need to reach sunlight, the more sunlight the better they can **photosynthesise**
Flowers need to be held up in the air, where insects/birds/wind can **pollinate** them
127
Why do roots grow downwards?
They grow down to **anchor** themselves in the soil
And to absorb **water and minerals** from between soil particles
128
Define auxin:
A plant hormone made in the tips of shoots, which causes cells to elongate
129
How does auxin move through the shoot?
It diffuses from the tip, into the rest of the shoot
130
How does auxin control positive phototropism in shoots?
Light shines onto a shoot from **all around** → auxin is distributed evenly around the tip of the shoot → cells elongate at the **same rate** → shoots grows **straight** upwards
Light shines onto shoot from **one side** → auxin at tip concentrates on **shady side** → cells on shady side grow faster than ones on bright side → so shoot bends **towards the light**
