AIMS – starter slide 5• Give back homework brain questions.• Starter.• Explain with diagrams and photographs, the

sliding filament model of muscular contraction.• Muscles, nerves and hormones “pulling together”.• Collect in muscle questions • Recap Plant Hormones.• Homework – Question 2 d) and e) 2011 paper and

question 6, 2010 paper. Find your ecology booklets to check through and bring on Thursday

True or false?• Restriction enzymes stick sugar-phosphate

backbones together.• A genetic probe is needed to allow DNA

polymerase to make a complementary strand of DNA in a PCR machine.

• Separation of DNA fragments by electrophoresis occurs from the +ve to the –ve electrode.

• Electrophoresis can separate fragments of DNA only one base different in length.

• The cycle of temperatures in the PCR is 95, 55 and 72°C.

• The PCR mixture includes DNA polymerase which has been taken from a thermophobic bacterium.

AIMS – pantomime and lunch from 1:00 – 1:45 today! Please collect statements of entry from

faculty desks.

• Promonitor 5• Check homework and give out revision

timetables.• Structure and mechanism of contraction in

skeletal muscle.• Energy for muscle contraction.• Homework – Exam question parts a) b) c) and

d) only.• Mock on Thursday 12th January after F211 on

the 11th. (F212 on the 18th and 215 on the 31st)

Promonitor 5• 24 marks – 30 minutes. Write 3 and 5 on

lined paper.

• Page 188, question 3 6 marks• Page 189, question 5 10 marks• On paper, question 6 c) 8 marks

• Now let’s check your homework - drawing on booklet page 5, + table page 1.

j) Outline the structural and functional differences between voluntary

(skeletal) involuntary (smooth) and cardiac muscle.

Skeletal - voluntary

Muscle fibre – asingle cell.

Nuclei

Stripes of muscle protein – actin and myosin.

Cardiac and Smooth (__________)Muscle

Nucleus Joins betweenmuscle cells

Intercalated disc

Spindle shaped cell

Single nucleus in cellmyocyte

Involuntary / Smooth – slow to contract and slow to fatigue.

Location Muscle Arrangement

Action

Intestinal walls ? Peristalsis

Iris of eye Circular and radial bundles

?

Arterial walls, cervix and uterus

? Contraction narrows _______. Relaxation dilates _________.

Circular and radial bundles

Contracting radialmuscle dilates pupil/circular constricts.

Circular bundles

Why do blood vessels not need longitudinal muscle to act against circular to cause dilation?

Cardiac Muscle – atrial, ventricular and excitatory and conductive.

• Some cells are myogenic meaning………… especially the SA Node.

• How do the SAN, AVN, Bundle of His and Purkyne fibres work together to organise the heart beat?

• Suggest why the wave of excitation only passes down Bundle of Hiss?

• How do intercalated discs, gap junctions and a latticework of interconnections help the excitation of action potentials pass quickly over the cardiac muscle?

j) Outline the structural and functional differences between voluntary

(skeletal) involuntary (smooth) and cardiac muscle.

Skeletal - voluntary

Muscle fibre – asingle cell.

Nuclei

Stripes of muscle protein – actin and myosin.

Voluntary / Skeletal

• Voluntary muscle cells form fibres about 100µm wide – containing several nuclei pushed to the outside – why?

• Antagonistic skeletal muscles move bones at the j_____ by contracting and so p_____ them where they are connected by ______.

• Define sarcolemma (_________), sarcoplasm (__________) and sarcomere (s______ c_________ u_____ of a _______). Also, sarcoplasmic reticulum (________ ________) and myofibrils (________ ____)

Skeletal / Voluntary Muscle

g) Explain with diagrams and photos the sliding filament model of muscle contraction

Muscle Fibre

Myofibrils from a muscle fibre

Muscle Fibre Structure – see page 7 in booklet and 236 in

book.

http://www.brookscole.com/chemistry_d/templates/student_resources/shared_resources/animations/muscles/muscles.html

• Part of a single myofibril – complete page 7 of booklet.

Actin

Myosin

1, 2, 3, 4, 5?

1

2

3

4

5Now check page 8

Describe what is happening and then complete page 10

Starter – Peer mark your questions (Pdf MS F215 Jan 2011)

• AIMS – Page 10 matching pairs.• Detail of myofibril structure pages 11

and 12• Tell each other story of contraction

using pipe cleaners and pages 13 and 14.

• Check order on page 23.• Energy for muscle contraction.• Pulling Together – nerves, hormones

and muscles.

Page 11 – 14. Animations1. http://www.brookscole.com/chemistry_d/templates/student_resources/

shared_resources/animations/muscles/muscles.html Quiz and basic parts of the myofibril

2. http://highered.mcgraw-hill.com/sites/0072437316/student_view0/chapter42/animations.html# sarcomere shortening

3. http://www.blackwellpublishing.com/matthews/myosin.html sliding filament4. http://highered.mcgraw-hill.com/sites/0072495855/student_view0/

chapter10/animation__myofilament_contraction.html myosin heads move

5. http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter10/animation__breakdown_of_atp_and_cross-bridge_movement_during_muscle_contraction.html

Detail!

6. http://www.getbodysmart.com/ap/muscletissue/contraction/contractioncycle/tutorial.html

good contraction cycle

Page 13 in booklet - h) Outline the role of ATP in muscular contraction http://www.youtube.com/watch?v=gJ309LfHQ3M&feature=related

Contraction!

1. When calcium arrives, it attaches to _____ which releases _______, and the myosin heads are ready with ADP and P attached.

2. Myosin head attaches to actin and P is released.3. Stored energy in head causes it to bend back

and sweep actin over the myosin.4. ADP is released.5. New ATP breaks cross bridge as it attaches to

myosin head.6. ATP is hydrolysed to ADP and P, releasing stored

energy into head.7. Myosin head returns to upright position.

See back page for simple version – put it in order.

MUSCLE CONTRACTION – SOME KEY WORDS

• Write sentences containing one or more of these words in their correct context.

Actin Myosin Tropomyosin Troponin

Calcium ATP ATPase Power stroke

Hydrolysis

Initiation of contraction• See page 15 of booklet.• What is missing from this animation?• http://www.blackwellpublishing.com/matthews/

nmj.html neuromuscular junction – not much

detail • http://highered.mcgraw-hill.com/sites/0072495855/

student_view0/chapter10/animation__action_potentials_and_muscle_contraction.html

• Starter above + quiz

• http://www.youtube.com/watch?v=hzXVe4RS8-A good long one

• Page 15 – check round room and then page 22 question

h) Outline how the supply of ATP is maintained in muscles

• Energy for muscle contraction See page 16 in booklet

• Circulating lactic acid stimulates a greater blood supply to muscles – why is this useful?

• Answer questions 1 – 3 page 237

k) Responses to environmental stimuli in mammals are coordinated by nervous and endocrine systems.

• What does that mean? Give an example.

• Page 238 – What do stimuli feed into the systems?

• Give 2 examples.• These survival strategies may be long

or short term – give examples of each.• How can the brain influence hormonal

secretion?

You feel threatened! Page 17

http://www.youtube.com/watch?v=Thuz44RgRMQ

What will happen to :

Pupils?Heart rate and blood pressure?Arterioles to digestive systemand skin?Arterioles to liver and muscles?Blood glucose level?Metabolic rate?Ventilation depth and rate?Sweat production?Erector pili muscles in skin?Endorphin (pain killers) in brain?

l) Explain how in mammals the “flight or fight” response to environmental stimuli is

coordinated by nervous and endocrine systems.

• Coordination• What kind of stimuli might elicit stress?• Which part of the brain would

“understand” the danger?• Which part of the brain will then be

stimulated to trigger the ________ NS and the secretion of ________ from the a_______ m________?

When threatened, apart from releasing adrenalin from the adrenal medulla……….the hypothalamus

releases….

ACTH (Adreno-corticotropic hormone)

Adrenal cortex 30 corticosteroids

Some help body resist stressors

CRF (corticotropin releasing factor) released into pituitary gland

What will be going on inside these dog’s brains and

physiology?

Try stretch and challenge and card sort.Why do they not run or fight immediately?

Have a great Christmas and feel in control of your revision

and work!

You feel threatened!• What will happen to :

• Pupils?

• Heart rate and blood pressure?

• Arterioles to digestive system• and skin?

• Arterioles to liver and muscles?

• Blood glucose level?

• Metabolic rate?

• Ventilation depth and rate?

• Sweat production?

• Erector pili muscles in skin?

• Endorphin (pain killers) in brain?