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Biology Higher Level > 6.6 > Flashcards

6.6 Flashcards

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1
Q

Define homeostasis

A

The ability to maintain a stable internal environment

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2
Q

What are the 5 common examples of homeostasis that the human body includes?

A
  1. Blood pH (7.35 - 7.45)
  2. Blood CO2 concentration
  3. Blood glucose concentration
  4. Body temperature (37c)
  5. Osmotic balance
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3
Q

How is homeostasis maintained?

A

The body have several negative feedback loops

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4
Q

What is negative feedback?

A

The processes that bring a value back towards a set point

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5
Q

What is the endocrine system?

A

A series of glands that produce hormones that circulate in the bloodstream to target tissues

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6
Q

How can homeostasis be achieved?

A
  1. Physically (e.g shivering)
  2. Chemically (e.g the produce of hormones)
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7
Q

List the glands found in the endocrine system

A
  1. Adrenal gland
  2. Thymus gland
  3. Thyroid gland
  4. Parathyroid gland
  5. Pineal gland
  6. Hypothalamus
  7. Pituitary gland
  8. Ovaries; F
  9. Testes; M
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8
Q

Define hormone

A

A lipid or protein based molecule that is secreted into the bloodstream by an endocrine gland; ONLY affect TARGETED tissues

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9
Q

How do hormones target specific cells?

A

Once the hormone secreting cell secretes the hormone into the bloodstream, the hormone will be distributed all over the body therefore the hormone will come in contact with a lot of different tissues

But only the target tissues are going to have a receptor to bind with the hormone

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10
Q

Where is thyroxin produced and what is the purpose of this hormone?

A

Secreted by the…
- Thyroid gland
Purpose
- Controls metabolic rate and body temperature

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11
Q

What are the problems that the different levels of thyroxin in the body can cause?

A

Too much thyroxin…
- Hyperthyroidism
- Leads to increased metabolism and temperature
Too little thyroxin…
- Hypothyroidism
- Leads to decreased metabolism

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12
Q

What is the huge and inflamed thyroid called?

A

Goitre; Swelling of the thyroid gland

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13
Q

Where is leptin produced and what is the purpose of this hormone?

A

Secreted by…
- The adipose tissue aka fat tissues
Purpose
- To decrease appetite
- The more a fat you have, the more leptin you secrete, the lower your appetite should become

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14
Q

What are the problems that high levels of leptin can cause?

A

You can become desensitised to leptin
- It doesn’t work in controlling your appetite anymore

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15
Q

Where is melatonin produced and what is the purpose of this hormone?

A

Secreted by…
- The pineal gland in the brain
Purpose/ function
- Regulates the day/ night cycle; The circadian rhythm
- Melatonin levels are highest at night time

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16
Q

What does melatonin help with?

A

It can help with jet lag

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17
Q

What are the 2 type of glands that the pancreas is considered as?

A

The pancreas is both an
1. Endocrine gland
2. Exocrine gland

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18
Q

State the difference between the exocrine gland and the endocrine gland

A

Exocrine glands send secretions to a specific location through a duct, it secretes
- Lipase
- Salivary amylase
- Trypsin

Endocrine glands secrete hormones that travels through the blood stream to target tissues

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19
Q

List the 2 hormones that are produced by the endocrine cells of the pancreas

A
  1. Insulin
  2. Glucagon
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20
Q

What type of cells produces insulin and where is that type of cell found in the body?

A

Insulin is produced in the beta cells
Beta cells can be found in the pancreas

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21
Q

What type of cells produces glucagon and where is that type of cell found in the body?

A

Glucagon is produced in the alpha cells
Alpha cells are found in the pancreas

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22
Q

Why must the level of blood glucose be maintained at a homeostatic level at all times?

A

Blood glucose maintains at a homeostatic level at all times

Glucose can affect the osmolarity of the red blood cells

Glucose is soluble in the blood plasma, the area outside of the cell. The glucose level inside and outside of the cell must be the same to maintain an isotonic environment, no net movement of water inside and outside of the cell

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23
Q

What does hypotonic mean?

A

When too much water enters the cell, causing the cell to swell up or burst
Cytolysis occurs

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24
Q

What does hypertonic mean?

A

Too much glucose in the blood plasma compared to the cell
The lack of glucose in the plasma causes excess water from the plasma to enter the cell via osmosis
The blood plasma becomes hypertonic
The water will diffuse out of the cell via osmosis
Therefore the cell will shrivel up, plasmolyse

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25
Q

How does the blood glucose level fluctuate in terms of the increase or decrease in the rate of respiration?

A

Cells that are in tissues that are suddenly…
Increasing the rate of respiration
- Requires more glucose than normal
Decreasing the rate of respiration
- Requires less glucose than normal

26
Q

Why does the blood glucose level fluctuate in terms of after a meal/eating?

A

After meals, carbohydrates are broken down into glucose molecules and are absorbed into the bloodstream

27
Q

Enzymes wise, who is glucose obtained?

A

Starch —Amylase—> Maltose
Maltose —> Glucose

28
Q

What regulates the evil of glucose in the blood stream?

A

Insulin and glucagon

29
Q

How does insulin help with the regulation of glucose levels?

A

Insulin causes the liver cells to…
- Absorb the glucose, removing it from the blood
- Turns liver cells into glycogen and stores it
- Causes the glucose protein channels in body cells to open so that some of the glucose goes into the cell

30
Q

How does glucagon help with the regulation of glucose levels?

A

Glucagon stimulates the liver cells to turn some of the stored glycogen into glucose and erases it to the blood stream

When all of your glucose is gone, you secrete glucagon

31
Q

How does glucagon molecules cause the blood glucose level to go up?

A

Glucagon causes glycogen molecules to be broken up into individual glucoses which would cause the blood glucose level to go up

32
Q

Describe Type 1 diabetes

A
  • Juvenile diabetes
  • Beta cells of pancreas don’t produce enough insulin
  • Controlled by insulin injections
  • An autoimmune disease, the body is attacking it’s own beta cells
33
Q

Describe Type 2 diabetes

A
  • Adult onset diabetes
  • Body cell (aka insulin receptors) receptors do not respond properly to insulin
  • Controlled by diet and exercises
  • Associated with genetics, obesity, lack of exercise, age/ ethnicity
34
Q

What might happen if diabetes is left untreated?

A
  • Blindness
  • Kidney failure
  • Nerve damage (chopping off your leg)
  • Poor wound healing
  • Increased risk of heart disease
35
Q

What is the major sex hormone in males?

A

Testosterone

36
Q

Describe the effects of testosterone in different points of a males life

A

Embryonic development
- Development of male genitalia
Puberty
- Development of secondary sex characteristics
Adulthood
- Sperm production
- Sex drive

37
Q

List the 8 parts of the male reproductive system and state their functions

A
  1. Testis: Sperm production
  2. Epididymis; Sperm maturation
  3. Scrotum: Holds testes outside the body at a lower temperature for sperm maturation
  4. Vas deferents: Carries mature sperm to urethra during ejaculation
  5. Seminal vesicles: Add seminal fluid to semen
  6. Prostate: Produces seminal fluid in carbohydrates to provide energy for sperm
  7. Penis: Becomes erect as a result of blood engorgement for ejaculation of semen
  8. Urethra: Tube which carries semen thorough the penis
38
Q

List the 6 parts of the female reproductive system and state their functions

A
  1. Ovaries: Produces oestrogen, releases the secondary oocyte and develops the corpus luteum
  2. Fallopian tube/ oviduct: Carries the egg or the embryo to the uterus
  3. Uterus: Muscular organ where the embryo implants and pregnancy occurs
  4. Endometrium: Highly vascular lining of the uterus
  5. Cervix: Narrow opening between the vagina and uterus that allows sperm to enter; expands pathway for childbirth
  6. Vagina: Muscular tube leading out of the body; place where semen is ejaculated into
39
Q

What are the sex chromosomes of a female?

A

XX

40
Q

What are the sex chromosomes of a male?

A

XY

41
Q

Which parent is responsible for determining the gender of a child?

A

Father because he carries the Y chromosome

42
Q

Explain how the presences of X or Y chromosomes result in development of female and male characteristics

A

If there are 2 X chromosomes, the alleles interact to produce oestrogen and progesterone, resulting in female development

If there is a Y chromosome present, testosterone is produced and male reproductive organs will form

43
Q

When will embryos begin sexual development?

A

Embryos don’t show sexual development until 8 weeks

44
Q

What is the role of male sex hormones during puberty?

A
  • Testosterone
  • Growth of facial, underarm, chest and public hair
  • Deepening of the voice
  • Increased muscle mass
  • Enlargement of the penis
45
Q

What is the role of female sex hormones during puberty?

A
  • Oestrogen and progesterone
  • Enlargement of breasts
  • Growth of pubic and underarm hair
  • Widening of hips
46
Q

How long does the menstrual cycle last for?

A

The menstrual cycle starts during puberty and each cycle lasts around 28 days

47
Q

What happens to the endometrium of there is no pregnancy occurred?

A

If no pregnancy occurs, the woman must shed this lining and prepare a new lining for the next cycle

48
Q

What does LH stand for?

A

Luteinising Hormone

49
Q

What does FSH stand for?

A

Follicle stimulating hormone

50
Q

What gland produces LH and FSH?

A

Pituitary glands

51
Q

What do LH and FSH act on in the female reproductive system?

A

The ovaries

52
Q

What are the effects of FSH and LH on the ovaries?

A

FSH and LH both triggers the follicle cells in the ovary to start secreting oestrogen

53
Q

What’s a follicle?

A

It is the structure surrounding an oocyte (an egg)

54
Q

What effects does the oestrogen have on the uterus?

A

Oestrogen increases the thickness of the endometrium

55
Q

What effects does the oestrogen have on the pituitary gland?

A

Oestrogen tells the pituitary to release more FSH and LH
An example of a positive feedback loop

56
Q

What is an oocyte?

A

An immature egg

57
Q

Describe the effects of FSH and LH on the ovaries?

A
  1. Immature egg; oocyte will move through the cycle
  2. FSH and LH causes the development of the follicle
  3. Follicle produces oestrogen which causes the pituitary to secrete even more LSH and LH
  4. The spike in FSH and LH causes the follicle into the fallopians tube (ovulation)
  5. The leftover follicle cells become corpus luteum.
  6. The corpus luteum produces progesterone, a hormone that thickens the endometrium
  7. If no pregnancy occurs, the compose luteum breaks down and progesterone production stops, causing the endometrium to shed (menstruation)
58
Q

Outline the events of the menstrual cycle (8)

A
  1. FSH stimulates the development of follicles
  2. FSH stimulates oestrogen secretion by the developing follicle
  3. Oestrogen stimulates the repair of the uterus lining
  4. Oestrogen stimulates LH secretion
  5. LH causes the development of the corpus luteum
  6. LH causes secretion of progesterone
  7. Progesterone causes thickening of the uterus lining/ prepares uterine lining for implantation
  8. Progesterone/ oestrogen inhibits the secretion of LH or FSH
  9. Falling progesterone levels at the end of the cycle allows FSH production/ menstruation
59
Q

What does IVF stand for?

A

In Vitro Fertilization

60
Q

Explain the normal conception and implantation of the oocyte

A
  1. Fertilisation occurs in the fallopian tubes 24 - 48 hours after ovulation
  2. Zygote divides by mitosis, travels through the fallopian tube and implants in the endometrium of the uterus
  3. Cells divide many more times, until it becomes an embryo
61
Q

What are some problems that couples faces with infertility?

A
  • Males with low sperm count
  • Males with impotences; the inability to sustain an erection for intercourse
  • Females who don’t ovulate normally
  • Females with blocked fallopian tube; presence of cysts/ scar tissues
62
Q

Explain the process of in vitro fertilisation

A
  1. Hormonal shots are given to the woman to stop the secretion of her own hormones
  2. Shots of FSH are given to produce a crap ton of follicles
  3. Eggs (oocytes) are harvested using needles
  4. A man ejaculates into a container
  5. Harvested eggs are mixed with the sperm cells
  6. Fertilised eggs are allowed to develop into embryos in a petri dish
  7. One or more healthy embryos are implanted in the women
  8. Pregnancy proceeds normally

Biology Higher Level (50 decks)

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