SB7 Flashcards
Animal coordination, control and homeostasis (94 cards)
1
Q
What are hormones
A
Chemical messengers
2
Q
How are hormones transported
A
Through the blood
3
Q
What is meant by the endocrine system
A
The various glands that secrete hormones into the blood
4
Q
What is the difference between the endocrine and nervous system
A
- ES uses chemical messengers, NS electrical impulses
- ES is slower and lasts longer, NS is quick and lasts shorter
- ES act generally, NS is precise
5
Q
What are the endocrine glands, hormones and location
A
- Pituitary - FHS, LH, ADH, TSH, TRH -brain
- Adrenal - Adrenaline - Above kidneys
- Thyroid - Thyroxine - Neck
- Pancreas - Insulin + Glucagon - Abdomen
- Ovaries - Oestrogen + Progesterone - Pelvis
- Testes - Testosterone - Pelvis
6
Q
Define homeostasis
A
The regulation of the internal conditions to maintain optimum conditions
7
Q
Define target cells/organs
A
Tissues that have receptors for specific hormones - allowing hormones to trigger sudden changes
8
Q
Why is it important to maintain homeostasis
A
To ensure the survival and function of all cells and the body
9
Q
What is negative feedback response
A
The body’s attempt to counteract and reverse any external or internal stimuli to maintain homeostasis
10
Q
Why is adrenaline produced
A
- The body has an increased demand for oxygen
- To prepare the body for action/ ‘fight or flight’
11
Q
State the target organs of adrenaline
A
- Heart
- Liver
12
Q
State the effects of adrenaline
A
- Increase blood pressure to increase oxygen + energy supply to muscles
- Increases blood sugar level - break down of glycogen stores
- Increased breathing rate (bronchioles widen)
- Increased heart rate
- Redirects blood flow to digestive system
- Pupil dilation
13
Q
Why is thyroxine produced
A
- To regulate metabolism
- To control body’s energy production
14
Q
State the target organs of thyroxine
A
- All cells
- Digestive system
15
Q
What is the negative feedback response loop of thyroxine
A
- Hypothalamus detects low level of thyroxine and releases TRH
- TRH stimulates pituitary to release TSH
- TSH stimulates thyroid to release more thyroxine
- Thyroxine levels become too high
- Inhibits release of TRH + TSH
16
Q
What is it called when you have too little thyroxine
A
Hypothyroidism
17
Q
What are the effects of hypothyroidism
A
- Weight gain
- Increased heart rate
- Loss of appetite
- Reduced fertility
18
Q
What is it called when you have too much thyroxine
A
Hyperthyroidism
19
Q
What are the effects of hyperthyroidism
A
- Weight loss
- Palpitations
- Irregular menstrual cycle
- Irritability
20
Q
State the target organs of insulin
A
- Most cells (respiration)
- Muscles
- Liver
21
Q
What is the target organ of glucagon
A
- Liver
22
Q
What are the effects of insulin
A
Tells tissues to absorb excess glucose (which then produces glycogen)
23
Q
What are the effects of glucagon
A
Tells tissues to break down glycogen to form glucose
24
Q
What is glycogen
A
The long term storage form of glucose
25
How is glucose absorbed into the bloodstream
Through the consumption of carbohydrates
26
What happens when the blood glucose levels are too high
- Pancreas detects this
- Releases Insulin
- Insulin binds to liver, muscles and most cells
- They absorb glucose and store it as glycogen
- Blood glucose levels fall back to normal
27
In what ways can blood glucose levels fall
- Vigorous exercise
- Skipping meals
28
What happens when the blood glucose levels are too low
- Pancreas detects this
- Releases glucagon
- Glycogen breaks down to form glucose
- Glucose released into bloodstream
- Blood glucose levels rise back to normal
29
What is the cause and effect of Type 1 diabetes
- Autoimmune disease
- Pancreatic cells are killed
- Little - no insulin produced
30
What is the cause and effect of Type 2 diabetes
- Lifestyle
- Body cells become resistant to insulin
- Not enough insulin is produced
31
How is Type 1 diabetes controlled
- Injecting insulin into the subcutaneous tissue of the thigh or abdomen
- Exercising a lot - muscles absorb more glucose
- Low carb/sugar diet
32
How is Type 2 diabetes controlled
- Low carb/sugar diet
- Exercising a lot
33
What are the four hormones involved in the menstrual cycle
- FSH
- Oestrogen
- LH
- Progresterone
34
What are the stages of the menstrual cycle
- Stage 1: Day 1-5, menstruation occurs, uterus lining breaks down
- Stage 2: Day 5-14, uterus lining builds up again
- Stage 3: Day 14, ovulation occurs
- Stage 4: Day 15-28: uterus lining is maintained in case of fertilisation
35
What is the function of **FSH** and what stage is it released in
- Stimulates maturation of egg and follicle
- Stage 1
36
What is the function of **oestrogen** and what stage is it released in
- Builds up uterus lining
- Stage 2
37
What is the function of **LH** and what stage is it released in
- Ruptures egg follicle and the remains form corpus luteum
- Stage 3
38
What is the function of **progesterone** and what stage is it released in
- Released from corpus luteum
- Maintains uterus lining
- Creates thick mucus
- Stage 4
39
Define puberty
When adolescents develop their secondary sex characteristics
40
Give examples of pubic changes
- Men grow facial hair
- Women develop breasts
41
Define contraception
An artificial method used to prevent pregnancy
42
What are the hormonal methods of contraception and how long do they last
- The pill - 1 day
- Patch - 1 week
- Injection - 3 months
- Implant - 3 years
- IUD - 5-10 years
43
How do hormonal contraceptives work
- They slowly release oestrogen and/or progesterone
- They inhibit the release of FSH and LH - egg cant mature
44
What are the advantages of hormonal contraceptives
+ Reliable
+ (Some) are long lasting
+ Reduced period pain
45
What are the disadvantages of hormonal contraceptives
- Do not protect from STI
- Cause nausea and headaches
- Weight gain
- Acne
- Change in blood pressure
46
What are the physical methods of contraception and how do they work
- Condom - catch and kill sperm
- Diaphragm - prevent sperm from entering the cervix
- Spermicide - kills sperm
- Copper IUD - kills sperm
47
How do physical contraceptives work
Prevent sperm from reaching egg
48
What are the advantages of physical contraceptives
+ They can protect from SDI
+ Quick and easy
49
What are the disadvantages of physical contraceptives
- Can break or tear
- Aren't 100% reliable
50
Define sterilisation
A surgery making a human incapable of producing offspring
51
How does sterilisation work
- Vasectomy - cutting and tying sperm ducts to prevent sperm leaving
- Tube ligation - fallopian tubes blocked and sealed to prevent egg reaching uterus
52
What is the most reliable form of contraception
- Abstinence
53
What is ART
- Assistive Reproduction Therapy
- Use of artificial hormones to trick body into producing an embryo
54
What is clomifene therapy
- Women's pituitary gland may not produce enough FSH
- A drug that contains FSH and LH is given to her
- Follicle can now mature and ovulation can occur
55
What is IVF
In Vitro Fertilisation
56
When is IVF considered
If clomifene therapy is ineffective
57
What are the steps of IVF
- Egg follicle maturation is stimulated via hormones
- Egg released by many follicles and are taken out of ovary into a lab
- Man's sperm is collected
- Eggs are fertilised (sometimes by injecting sperm into egg ICSI)
- Multiple embryos are placed back into the uterus
58
Advantages of IVF
+ Infertile couples have a chance at having children
+ Unused embryos can be donated
59
Disadvantages of IVF
- Expensive
- Not always successful
- Multiple births increase chance of complications e.g. miscarriage
60
Define osmoregulation
Maintenance and regulation of water levels in blood
61
What roles do the kidneys have
- Regulate water levels
- Regulate ion levels
- Remove waste
62
What happens if an animal cell is placed in a **hypotonic** solution
- Hypotonic - higher concentration of water outside of cell
- Water moves into cell
- Cell becomes turgid
- Lysis occurs (no cell wall to keep structure)
63
What happens if an animal cell is placed in a **hypertonic** solution
- Hypertonic - higher concentration of water inside cell
- Water moves out of cell
- Cell becomes flaccid
- Crenation occurs (membranes wrinkles)
64
What organ is responsible for managing water levels
Kidney
65
What is a nephron
A filtration unit in the kidney
66
How does blood flow to the kidney
Through the renal artery
67
How does blood flow out of the kidney
Through the renal vein
68
What is urea
The products of deamination
69
What is deamination
The breakdown of excess amino acids in blood
70
Why is it important to filter out urea
It is slightly poisonous
71
Explain the process of filtration (kidneys)
- Liquid part of blood is forced out of **glomerulus** into the **Bowman's capsule** at a high pressure
- Bigger molecules (protein and blood cells) are too large to be forced through
72
Explain the process of selective reabsorption
- Fluid passes through proximal convulated tubule - loop of Henle - distal convulated tubule - collecting duct
- As fluid passes necessary substances are reabsorbed
- All glucose, some water + ions
73
What is urine
Anything that flows out of the collecting duct
74
How is urine excreted
It passes through the ureters to the bladder to the urethra
75
How does the negative feedback response work in osmoregulation
- Hypothalamus monitors and detects changes in water level
- If water levels decrease, it sends signal to pituitary to release ADH
- ADH increases the permeability of the collecting duct = more water reabsorbed
- Less urine produced
76
What is ADH
Anti-diuretic hormone
77
What is the danger of kidney failure
- Unable to regulate water + ion levels
- Unable to remove waste
78
Explain the process of dialysis
- Patients blood flows through dialysis fluid in a semi permeable membrane
- DF contains attributes of healthy blood e.g. normal water + ion levels, glucose, amino acids
- Concentration gradient established between blood and DF
- Excess water + ions, urea etc. diffuse out through the semi permeable membrane
- Filtered blood is put back into body
79
Why is the dialysis fluid constantly replaced
Concentration gradient will eventually reach equilibrium
80
Advantages of dialysis
+ Available to anybody
+ No drugs taken
81
Disadvantages of dialysis
- Time consuming (9-16h a week)
- Lifelong commitment
- Expensive
82
Describe features of a kidney transplant
- New kidney is placed lower - close to bladder
- New kidney is first tested for at least six matched antigens - reduce chance of rejection
83
Advantages of kidney transplant
+ Cheaper for NHS overall
+ Patients can lead a normal life
84
Disadvantages of kidney transplant
- Only lasts 8-9 years
- Need immunosuppressive drugs
- Surgery is risky
- Hard to get organs
- Chance of rejection
85
Define thermoregulation
Maintenance of temperature levels
86
Why is thermoregulation important
To ensure enzymes do not denature
87
Describe the role of the hypothalamus in thermoregulation
- Has a thermoregulatory centre that receives signals from heat receptors in the epidermis and the dermis
- Skin detects external temperature
88
Describe what happens if you are too hot
- Sweating
- Vasodilation
89
Purpose of sweating
- Water excreted evaporates = increase heat loss
90
Process of vasodilation
- Arteriole dilates - smooth muscle in walls dilate
- Increased blood flow to capillaries (close to skin surface)
- Increased heat loss out of body
- Less flow of blood through shunt vessel
91
Describe what happens if you are too cold
- Shivering
- Goosebumps
- Vasoconstriction
92
Process of shivering
- Repetitive muscles contractions = increased respiration in muscles = increased energy out
- Heat produced
93
Process and purpose of goosebumps
- Pili erector muscles contract
- Hairs trap insulating bubble or air
- Increase heat
94
Process of vasoconstriction
- Arteriole constricts - smooth muscle wall contracts
- Less blood flow to capillaries
- Less heat lost through skin
- More blood flows through shunt valve = reduce heat loss
