B5 Homeostasis & Response Flashcards
<p>What is <b>Homeostasis</b>?</p>
<p style="text-align: center;">Homeostasis is the regulation of the internal conditions of a cell or organism to maintain optimum conditions for function in response to internal and external changes.</p>
<p>What three internal factors are controlled by Homeostasis in the human body?</p>
<ul><li>Body Temperature</li><li>Blood Glucose Concentration</li><li>Water content in blood and cells</li></ul>
<p>Why does homeostasis maintain optimum conditions?</p>
<p>Homeostasis maintains optimum conditions for:</p>
<ul><li>Enzyme Action</li><li>Cell Structure</li><li>Chemical Reactions</li> so the can function in optimum conditions</ul>
<p>What are the two types of responses that are used to control conditions in the human body?</p>
<ul><li>The Nervous System</li><li>The Endocrine System (Hormones)</li></ul>
<p>What is the order of how the human nervous system works?</p>
<p>Stimulus→Receptor→Sensory Neurone→Relay Neurone→Coordination Centre→Motor Neurone→Effector→Response</p>
<p>What is a <b>receptor cell</b>?</p>
<p>A receptor cell is a cell that detects stimuli (changes in the internal or external environment)</p>
<p>What is the purpose of a <b>coordination centre</b>?</p>
<p>Coordination centres receive and process information from receptor cells and then send out signals to coordinate the response of the body</p>
<p>Name the three coordination centres in the human body?</p>
<ul><li>Brain</li><li>Spinal Cord</li>Pancreas</ul>
<p>Name the two types of effectors?</p>
<ul><li>Muscles</li><li>Glands</li></ul>
<p>What do effectors do to bring about a response?</p>
<ul><li>Muscles will contract</li><li>Glands secrete enzymes/hormones</li></ul>
<p>What is a <b>Negative Feedback loop</b>?</p>
<p>A continuous cycle of events that responds when conditions change away from the optimum point and causes it to return conditions back to this optimum point</p>
<p>What is the role of the Human Nervous System?</p>
<p>The Human Nervous System enables humans to react to their surroundings and coordinate their behaviour</p>
<p>What are the two organs in the <b>Central Nervous System</b>?</p>
<ul><li>Brain</li><li>Spinal Cord</li></ul>
<p>What is the purpose of the <b>Peripheral Nervous System</b>?</p>
<p>The Peripheral Nervous System carries information to and from the CNS</p>
<p>What are the three types of neurons?</p>
<ul><li>Sensory (Receptor Cells→CNS)</li><li>Relay (CNS→CNS)</li><li>Motor (CNS→Effector [Muscle or Gland])</li></ul>
<p>What is a <b>synapse</b>?</p>
<p>A synapse is a gap between two neurons</p>
<p>What is the <b>Endocrine</b> system?</p>
<p>The endocrine system is the collection of glands that produce hormones that regulate internal conditions</p>
<p>Name the hormone that controls the 'flight or fight' reaction in humans</p>
<p>Adrenaline</p>
<p>Where is <b>adrenaline</b> produced?</p>
<p>Adrenal Gland</p>
<p>What are the effects of adrenaline on the body?</p>
<ul><li>Increases heart rate<ul><li>This increases the delivery of oxygen and glucose to the brains and muscle</li></ul></li></ul>
<p>Where is <b>Thyroxine</b> made?</p>
<p>Thyroid Gland</p>
<p>What does Thyroxine do to the body?</p>
<p>Thyroxine increases the basal metabolic rate which increases growth and development?</p>
<p>What is <b>Negative Feedback</b>?</p>
<p>Negative feedback is a mechanism used by the body to bring its internal environment back to normal when the level of something gets too high or too low</p>
<p>How is Thyroxine controlled?</p>
<p>Thyroxine is controlled by Negative Feedback</p>
<ul><li>The <b>hypothalamus</b> monitors the concentration of Thyroxine in the blood</li><li>If levels of Thyroxine are too low, the hypothalamus produces <b>thyroid releasing hormone (TRH)</b></li><li>TRH stimulates the <b>pituitary gland</b> to produce <b>thyroid stimulating hormone (TSH)</b></li><li>TSH stiulates the <b>thyroid gland</b> to produce thyroxine</li><li>When thyroxine levels return back to normal, TRH is no longer released - causing the production of TSH to stop</li></ul>
What internal conditions are controlled by negative feedback?
- Thyroxine levels
- Temperature
- Water levels
- Blood sugar levels
How are hormones transported around the body?
Via the bloodstream
What is monitored for changes in glucose concentration?
The blood
What controls the response to changes in blood glucose concentration?
The Pancreas
What hormone is produced if blood glucose concentration is too high?
Insulin
How does insulin help lower blood glucose concentration?
Insulin causes glucose to move from the blood to the cells and triggers the conversion of glucose into glycogen
What hormone is produces if glucose concentration is too low?
Glucagon
How does glucagon help increase blood glucose concentration?
Glucagon triggers the breakdown of glycogen into glucose, which is released into blood
Where is glycogen stored?
- Muscle cells
- the Liver
Compare the speed and duration of hormonal contolled compared to nervous control
Hormones are slower to act but act for longer as they are effective up to when the hormone is broken down
How is Type 1 diabetes caused?
Type 1 diabetes is caused by an inability to make insulin in the pancreas
How is Type 2 diabetes caused?
Type 2 diabetes is caused | a lack of response by cells to insulin
What are some secondary sexual characteristics that occur during puberty for males?
- Hair growth on the face, pubic region and under arms
- Voice deepens
- growth spurt
- Sperm production
What are some secondary sexual characteristics that occur during puberty for females?
- Breasts develop
- Hips widen
- Hair growth in pubic area and under arms
- Growth spurt
- Menstrual cycle
What is the main female hormone involved in development and reproduction?
Oestrogen
What is the main male hormone involved in development and reproduction?
Testosterone
Which gland produces Testosterone?
Testes
Which gland produces oestrogen?
Ovaries
What does Testosterone cause to happpen in men?
Stimulates sperm production
What does Oestrogen cause to happen in women?
Menstural cycle
How often is an egg released from the ovaries?
Around 28 days
What does Follicle Stimulatin Hormone (FSH) cause?
FSH matures the eggs in the ovaries
What does Luteinising Hormone (LH) cause?
LH stimulates the release of an egg from the ovaries
Which hormones are involved in the maintenance of the uterus lining
Oestrogen & Progesterone
How do Oral Contraceptives containing hormones prevent pregnancy?
It inhibits FSH production so no eggs mature
How does an injection, implantation or skin patch containing slow release progesterone prevent preganacy?
Progesterone inhibits the maturation of eggs
How do barrier methods, such as condoms or diaphragms, prevent pregnancy?
Barrier methods prevent sperm reaching the egg
How do Intrauterine devices prevent pregnancy?
Intrauterine devices prevents the implantation of an embryo AND/OR releases hormones
How does spermicide prevent pregnancy?
Spermicide kills/disables sperm
How does surgical sterilisation prevent pregnancy?
Prevents sperm or egg being released by a male of female
What are Neurotransmitters?
Neurotransmitters are chemicals that diffuse across synapes and bind to receptors on the next neurone
What is a Reflex Action?
A Reflex Action is an unconcious response that allows a person to respond to dangerous situations automatically and rapidly via a reflec arc
What is a Reflex Arc?
A Reflex Arc is a neural path that controls a reflex
What are the Components of a Reflex Arc?
Stimulus→Receptor→Sensory Neurone→Motor Neurone→Effector→Response
How do Neurones work?
- An electrical impulse reaches the end of the Neurone before the synapse
- This triggers the release of chemicals called electrotransmitters
- The Neurotransmitters diffuse across the synapse (gap) between the neurones
- The neuortransmitters bind to receptors at the end of the next neurone
- The presence of the neurotransmitter causes the production of a new electrical impulse in the next neurone
What is a synapse?
A synapse is a junction between neurones
Why is it hard to treat brain damage or problems in the brain?
We don't understand the brain well
What are the three main parts of the brain?
- Medulla
- Cerebellum
- Cerebral Cortex
What is the Medulla responsible for?
The Medulla is the part of the brain that controls unconcious activities. This includes breathing and heartbeat
What is the Cerebellum responsible for?
The Cerbellum is responsible for muscle coodination. This includes Movement, posture, balance and speech
What is the Cerebral Cortex responsible for?
The Cerebral Cortex is responsible for concious thought. This includes memory, language and intelligence
What is the function of the Cornea?
The transparent frontal part of the eye that refracts light
What is the function of the Sclera?
The white of the eye is the opaque protective outer layer
What is the function of the Optical Layer?
The Optic Layer transmits (sends) visual information (as electrical impulses) from the retina to the brain
What is the function of the Retina?
The Retina is full of receptor cells, which are sensitive to both the brightness (light intensity) and the colour of light
What is the function of the Pupil?
The Pupil is a hole in the centre of the iris, through which light passes
What is the function of the Iris?
The Iris controls pupil diameter and the quantity of light reaching the retina
What is the function of the Suspensory Ligaments?
Suspensory Ligaments is ring of fibres that connect ciliary muscles to the lens
What is the function of Ciliary Muscles?
Ciliary Muscles are a ring of smooth muscle that changes the shape of the lens to focus light
