Human Physiology Flashcards

1
Q

Which features of the alveoli adapt them to gaseous exchange?

A
  • Single layer of cells.
  • Film of moisture.
  • Dense network of capillaries.
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2
Q

Where do motor neurons conduct impulses from and to?

A

From the central nervous system to effectors.

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3
Q

Which feature of striated muscle cells allows them to be considered as a possible exception to cell theory?

A

They contain more than one nucleus.

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4
Q

Where can 70s ribosomes be found?

A

In prokaryotic cells.

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5
Q

Which is the correct statement concerning HIV and AIDS?

A

All AIDS patients have HIV.

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6
Q

Which of the following is correct for lipase?

A

Substrate: Triglycerides
Source: Pancreas
pH - 7

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7
Q

What is the body’s response to low blood glucose levels?

A

Alpha cells in the pancreas secrete glucagon.

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8
Q

What causes the atrioventricular valve to close during a heartbeat?

A

Pressure in the atria is lower than the ventricles.

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9
Q

What happens to the external and internal intercostal muscles and diaphragm when inhaling?

A

External intercostal muscles: Contract
Internal intercoastal muscles: Relax
Diaphragm: Contracts

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10
Q

What feature of arteries is most important in maintaining sufficiently high blood pressure?

A

Elastic fibres in the wall.

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11
Q

Testosterone is a hormone that is important for male reproductive development. To which group of compounds does testosterone belong?

A

Lipids

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12
Q

What is a feature of phagocytic white blood cells?

A

Form part of non-specific immunity.

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13
Q

How do neonicotinoid pesticides cause paralysis and death in insects?

A
  • Acetylcholine receptors are blocked.
  • Cholinesterase fails to break down the pesticides.
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14
Q

A female is overweight. feels cold and tired and often fails to ovulate during the menstrual cycle. Which two hormones are probably secretes at insufficient levels?

A

LH and thyroxin.

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15
Q

When the left ventricle is relaxed, what is the state of the valves?

A

Atrioventricular valve: Open
Semilunar valve: Closed

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16
Q

Which of the following tissues would be found in the human ileum and stomach
I Mucosa
II Smooth muscle
III Villi

A

I Mucosa
II Smooth muscle

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17
Q

Where in the human heart would the pressure of the blood be highest?

A

Left ventricle

18
Q

Which of the following are known as increasing the risk of developing lung cancer?

A

I Tobacco smoke
II Radon gas
IV Asbestos dust

19
Q

Which of the following are involved in changing the rate of the heart beat?
I Medulla oblongata
II Adrenaline (epinephrine)
III Baroreceptors
IV AV node

A

I Medulla oblongata
II Adrenaline (epinephrine)
III Baroreceptors

20
Q

Florey an Chain tested penicillin on…

A

Bacterial infections in mice and humans

21
Q

Which of the following statements about pneumocytes is correct?

A

Type 1 pneumocytes: Exchange respiratory gases
Type II pneumocytes: Secrete surfactant

22
Q

Which of the following statements is a correct summary of inspiration?
A. Diaphragm and rib cage move down and flatten, decreasing lung air pressure
B. Diaphragm and rib cage move up and down, decreasing lung air pressure
C. Diaphragm flattens and rib cage moves upwards and outwards, decreasing lung air
pressure
D. Diaphragm flattens and rib cage moves upwards and outwards, increasing lung air
pressure

A

C. Diaphragm flattens and rib cage moves upwards and outwards, decreasing lung air
pressure

23
Q

The myelination of nerve fibres causes:
A. More accurate nervous transmission
B. Sensory stimulation
C. Saltatory transmission
D. The use of less neurotransmitter

A

C. Saltatory transmission

24
Q

Depolarisation of the neuron membrane is caused by
A. The sodium pump
B. The outflow of potassium ions
C. Active transport
D. The opening of sodium channels

A

The opening of sodium channels

25
Q

Which is the correct sequence of events in transmission across a chemical synapse?

A

Fusion of synaptic vesicles with the presynaptic membrane

Diffusion of neurotransmitter across the synaptic cleft

Neurotransmitter binds to receptors on the post synaptic membrane

Sodium ions enter the post synaptic membrane

26
Q

Describe how leptin is involved in controlling the appetite.

A

Secreted by adipose/fat storage tissue
Transported in blood
(Target organ) is the hypothalamus
Suppresses appetite/reduces food intake

27
Q
  1. In vitro fertilisation usually involves hormonal treatment that regulates the menstrual cycle. Give one reason why this is necessary to maximise the possibility of successful treatment.
A

Overproduction/harvesting of large numbers of ovae/reduction in invasive treatment
Regulating/controlling menstrual cycle for harvesting ovae/implanting
Maximising success of zygote (reintroduced at correct point of cycle)

28
Q
  1. Describe the role of the SRY gene in determining gender in humans.
A

SRY determines male gender
On Y chromosome
Stimulates the production of TDF
Causes development of male gonads (in foetus)

29
Q

Explain how the damage to lung alveoli causes an emphysema patient to have rapid ventilation

A

Collapse / damage / thickening of alveoli walls / pneumocytes
Gas exchange reduces because of a reduced surface area of alveoli
O2 concentration in blood decreases / blood CO2 concentration increases / lower pH of blood
Respiratory centre of the brain / homeostasis increases ventilation rate (medulla oblongata - but not required)

30
Q

Dialysis tubing can be used to model absorption in the human intestine. Outline two ways in which this model is limited as a representation of the living system.

A

Anatomic – no microvilli/absorptive epithelium/tissue layers
Physiological – simple diffusion/no active transport/facilitated diffusion

31
Q

List four factors that increase the risk of heart attacks and coronary thrombosis.

A

High blood glucose levels/diabetes
Smoking/nicotine intake
High blood cholesterol levels
Long term/chronic high blood pressure
Obesity
Lack of exercise
Genetic predisposition

32
Q

Antibiotic resistance is an increasingly serious medical problem. Describe two measures which can be taken to limit the increase in the numbers of resistant strains of bacteria.

A

High hygiene standards; Prevents the transfer of bacteria;
Minimise antibiotic prescription; Reduces exposure of bacteria to antibiotics;
Completing a course of antibiotic treatment; Prevents resistant bacteria surviving to reinfect host.;
Avoiding mass usage of antibiotics e.g. in animal farming; reduces exposure of bacteria to antibiotics;
Research to develop new antibiotics; Provides more antibiotics which have less resistant strains of bacteria:

33
Q

Neonicotinoid pesticides bind irreversibly to cholinergic receptors. Describe how this mechanism allows them to be efficient pesticides.

A

Receptors in post-synaptic membrane
Remain bound to receptor
Prevent binding of transmitter
(Therefore) prevent post synaptic excitation
Effectors are not stimulated

34
Q

What happens during inspiration?

A

The volume inside the thorax increases and consequently the pressure decreases.

The diaphragm contracts.

Muscles in the abdomen wall relaxes.

External intercostal muscles contracts.

Internal intercostal muscles relaxes.

35
Q

What happens during expiration?

A

The volume inside the thorax decreases and consequently the pressure increases.

The diaphragm relaxes.

Muscles in the abdomen wall contracts.

External intercostal muscles relaxes.

Internal intercostal muscles contracts.

36
Q

Outline the negative and positive feedback loops at the end of the follicular stage

A
  • Estrogen rises to a peak towards the end of the follicular stage. It stimulates the repair and the thickening of the endometrium and an increase in FSH receptors that makes the follicles more receptive to the hormone - FSH, boosting estrogen production. (positive feedback loop).
  • When it reaches high level, estrogen inhibits the secretion of FH, and stimulates LH secretion. (negative feedback loop).
37
Q

What happens to the hormone LH, at the end of the follicular phase?

A
  • LH rises to a sudden sharp peak at the end of the follicular phase.
  • It stimulates the completion of meiosis in the oocyte and partial digestion of the follicle wall allowing it to burst open at ovulation.
  • LH promotes the development of the wall of the follicle after ovulation into the corpus luteum which secretes estrogen (positive feedback loop) and progesterone.
38
Q

Outline the negative feedback that occurs at the start of the luteal phase

A
  • Progesterone levels rise at the start of the start of the luteal phase and then drops back to the low level by the end of this phase.
  • Progesterone promotes the thickening and maintenance of the endometrium.
  • Progesterone inhibits the secretion of FSH and LH secretion by the pituitary gland (negative feedback).
39
Q

Outline the roles of FH and LH in the menstrual cycle

A
  • FSH and LH are protein hormones produced by the pituitary gland that bind to FSH and LH receptors in the membranes of follicle cells.
  • These pituitary hormones stimulates the growth of several ovarian follicles, each containing one egg.

-Stimulates follicular growth and ovulation.

40
Q

Outline the roles if estrogen and progesterone in the menstrual cycle.

A
  • Estrogen and progesterone are ovarian hormones, produced by the walls of the follicle and corpus luteum. They are absorbed by many cells in the female body, where they influence gene expression and therefore development.
41
Q

Outline the steps of in vitro fertilization

A
  1. The woman takes a drug each day which stops the pituitary gland from secreting LH and FSH hormones.
  2. Secretion of estrogen and progesterone therefore stops.
  3. Intramuscular injections of FH and LSH are then given daily for about 10 days, to stimulate follicles to develop.
  4. Superovulation occurs as more FSH is injected than usually, promoting further development of follicles.
  5. Follicles become mature when being stimulated by the injection of HCG.
  6. A micropipette mounted on an ultrasound scanner is passed through the uterus wall to wash out the eggs and the sperm cells in sterile conditions in a shallow dish which is then incubated in a shallow dish which is then incubated at 37 degrees, until the next day.

7.Embryos are placed in the woman’s uterus when they are 48 hours old.

  1. Extra progesterone tablet is placed in the vagina to ensure that the endometrium is thickened and lined.